First off, I've been reading this forum for awhile and have been able to find plenty of great information provided by all the members here. So thanks to everyone who contributes here for me not having to make my first post before today.

The Basics:
2001 Convertible, 90k, manual, fully stock as far as I'm aware

The Issues:
For the past few weeks, I've had a rough idle maybe 2-3 times a week when starting the car up in the morning. After about 30 seconds, it stabilized and all was well. This may or may not be related, but felt it was relevant info.
Twice last week shortly after starting the drive home from work, the car had a really jerky stretch right around hitting 5-10 mph. I'm not really sure how best to describe this other than to say it felt pretty similar to when my dad was teaching me how to drive a stick and I would release the clutch too fast and the car would jerk us back and forth before almost stalling. Jerking, jarring, bumping...are the best ways I can think to describe what was happening. I hope that makes sense.
This would only happen the first 1-2 times I would start from a standstill. After that, all was fine for the remainder of the ride home.
The first time it happened, I jotted down the codes on the display and reset them afterwards.
This past week, it started happening more often, but would still only happen the first 1-2 times I would start from a standstill. The CEL actually came on this time, and the P0102 error was listed when I went through the codes. I also noticed the oil pressure would spike to about 65-80 while it went through the rough phase.
After doing some quick research, I replaced the MAF sensor and the air filter thinking that would be an easy fix for what seemed to be the common problems related to this code. (Note: I was only able to get the cheaper $87 version of the MAF sensor)
While replacing the MAF sensor, I visually inspected the intake duct and all relevant hoses and wires. Only thing that jumped out to me was the duct had a pretty bad crimp in it where it attaches to the Throttle Body, as if someone had tightened the clamp without it being attached properly. I ensured this was attached correctly this time.
After replacing the MAF sensor and the air filter, it's still experiencing the same issues, so I'm at a loss at this point and was hoping to get some assistance on what to test next. Any help would be appreciated, thanks in advance.

 

I looked at the connector and the wires up to where they split off from the other wires and didn't see anything that looked out of place, but hard to know for sure when the wires are wrapped up. Is this something I could test with a multimeter? I don't have any schematics for the vehicle, so don't know exactly what I would be trying to check.

Yeah, I would definitely do that based on what is wrong. In this case, I wasn't too concerned about spending <$100 and 15 minutes to replace an almost 20 year old part that seems to have common problems among these models.

 

I put in the Information on this code as well as the schematic for the MAF sensor. It should help you track down the issue. Peobably a good idea to check the voltages at the connector.


DTC P0102
Circuit Description
The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal in order to provide the correct fuel delivery for a wide range of engine speeds and engine loads. A small quantity of air entering the engine indicates a deceleration, or an idle. A large quantity of air entering the engine indicates an acceleration, or a high load situation. The MAF sensor has an ignition 1 voltage circuit, a ground circuit, and a signal circuit. The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on the inlet air flow through the sensor bore. The frequency will vary within a range of around 2,000 Hertz at idle, to about 12,000 Hertz at the maximum engine load. DTC P0102 will set if the PCM detects a frequency signal lower than the possible range of a normally operating MAF sensor.

Conditions for Running the DTC
The engine is running for greater than 0.5 second.
The engine speed is at least 300 RPM.
The ignition 1 signal is at least 8 volts.
Conditions for Setting the DTC
The MAF sensor frequency signal is less than 10 Hz.
The above condition is present for greater than 1.2 seconds.
Action Taken When the DTC Sets
The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
Diagnostic Aids
Inspect for the following conditions:

A misrouted harness. Inspect the MAF sensor harness in order to ensure that it is not routed too close to the following sensors or components:
The ignition coils
Any solenoids
Any relays
Any motors
A low minimum air rate may cause this DTC to set during deceleration. Inspect for the following conditions:
A plugged or collapsed intake air duct or a dirty air filter element
Objects blocking the MAF sensor air inlet screen
Throttle bore and throttle plate deposits
A wide open throttle (WOT) acceleration from a stop should cause the MAF display on a scan tool to increase from about 4-7 g/s at idle to about 190 g/s or more at the time of the 1-2 shift. If not, inspect for a restriction.
Any unmetered air entering the engine may cause this DTC to set. Inspect for vacuum leaks anywhere downstream of the MAF sensor.
If you suspect the vehicle condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Wiring Systems.

If an intermittent exists, refer to Intermittent Conditions .

Test Description
The numbers below refer to the step numbers on the diagnostic table.

This step verifies the signal circuit from the MAF sensor electrical connector to the PCM. A voltage reading of less than 4 volts or greater than 6 volts indicates a malfunction in the wiring or a poor connection.

This step tests the signal circuit of the MAF sensor for a short to another 5 volt reference circuit.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Install a scan tool.
Start the engine.
With a scan tool, observe the MAF sensor frequency parameter.
Does the scan tool indicate that the MAF sensor frequency is less than the specified value?

10 Hz

Go to Step 4

Go to Step 3

3

Observe the Freeze Frame/Failure Records for this DTC.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records that you observed.
Does the DTC fail this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4

Inspect the fuse that supplies the Ignition 1 voltage circuit of the MAF sensor. Refer to Engine Controls Schematics .

Is the fuse open?

--

Go to Step 14

Go to Step 5

5

Turn OFF the ignition.
Disconnect the MAF sensor harness connector.
Turn ON the ignition, with the engine OFF.
Measure the voltage from the signal circuit of the MAF sensor to a good ground. Refer to Circuit Testing in Wiring Systems.
Does the voltage measure near the specified value?

5 V

Go to Step 6

Go to Step 8

6

Connect a 3-amp fused jumper wire between the signal circuit of the MAF sensor and a good ground. Refer to Circuit Testing in Wiring Systems.
Start the engine.
Do any additional DTCs set?

--

Go to Step 16

Go to Step 7

7

Turn OFF the ignition.
Connect a test lamp between the Ignition 1 voltage circuit of the MAF sensor and the ground circuit of the MAF sensor. Refer to Circuit Testing in Wiring Systems.
Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?

--

Go to Step 18

Go to Step 11

8

Does the voltage measure less than the specified value?

4.5 V

Go to Step 10

Go to Step 9

9


important
Disconnecting the PCM connectors may eliminate the short to voltage if the signal circuit is shorted to another PCM circuit. Refer to Circuit Testing in Wiring Systems.

Turn OFF the ignition.
Disconnect the PCM. Refer to Powertrain Control Module (PCM) Replacement
Turn ON the ignition, with the engine OFF.
Measure the voltage from the signal circuit of the MAF sensor to a good ground.
Does the voltage measure near the specified value?

0 V

Go to Step 12

Go to Step 15

10

Turn OFF the ignition.
Disconnect the PCM. Refer to Powertrain Control Module (PCM) Replacement
Test the signal circuit between the PCM and the MAF sensor for the following conditions:
A high resistance or an open
A short to ground
A short to the ground circuit of the MAF sensor-- Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

--

Go to Step 22

Go to Step 12

11

Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and a good ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

--

Go to Step 13

Go to Step 14

12

Test for continuity at the harness connector of the PCM from the signal circuit of the MAF sensor to all other circuits at both PCM connectors. Refer to Circuit Testing in Wiring Systems.

Does the DMM indicate continuity between any other circuit?

--

Go to Step 17

Go to Step 19

13

Repair the high resistance or an open in the ground circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 22

--

14


Important
The ignition 1 voltage circuit of the MAF sensor is spliced to other components on the vehicle.

Repair the short to ground or an open in the ignition 1 voltage circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.
Replace the fuse if necessary.
Did you complete the repair?

--

Go to Step 22

Go to Step 20

15

Repair the short to voltage in the signal circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 22

--

16

Repair the short between the signal circuit of the MAF sensor and the circuit for which the DTC set. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 22

--

17

Repair the circuits that are shorted together. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 22

--

18

Inspect for poor connections at the harness connector of the MAF sensor. Refer to Testing for Intermittent and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 20

19

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 21

20

Replace the MAF sensor. Refer to Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement

Did you complete the replacement?

--

Go to Step 22

--

21

Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement

Did you complete the replacement?

--

Go to Step 22

--

22

Use the scan tool in order to clear the DTCs.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC run, and pass?

--

Go to Step 23

Go to Step 2

23

With a scan tool, observe the stored information in Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK

 

this is exactly what I was going to suggest... I just recently went through a similar issue on my car and when making wot pulls it would set tps sensor codes as well as traction codes and then go into reduced engine power but under other conditions the car ran perfect... when I pulled the tps connector out I found 1 pin that had opened up quite a bit, it also happened to be the tps signal wire... I have no idea how the pin opened up like that but it was the culprit... some of the sensors work on very small voltage ranges so if you interrupt that reading in the slightest it can cause things to go haywire... inspect your maf connector for something like this, notice the pin are the far left compared to the others

 

I pulled the MAF harness and the first thing I noticed is all five wires were white. I haven't seen any others like this, so I'm guessing there was some previous work done. I was able to find a diagram that said that the pins were A-E if you were looking at the connector with the latch on the bottom, so that's what I've used below.

My multimeter was shot, so I ran out and bought a cheap digital one. The instructions on this were non existent and the readings didn't really make much sense to me for a 12V DC system. Below is what was displayed on the meter, maybe someone more knowledgable can interpret the readings better.

With the ignition on, engine off:
A - 26 mV
B - Open Loop
C - 20 mV
D - Open Loop
E - 13.5 mV

The pins looked ok from a visual inspection, but that doesn't mean I'm not overlooking something. The part that stumps me is that it only does it after a cold start. Once the engine is warm, there's no more bucking. If I start the car and let it run for 5-10 minutes, it will drive without any problems.

I'm not sure what my next step should be. Should I be parking the car until I can get this figured out, or is it unlikely to do any major damage (other than the potential whiplash)?

 

Last week I let the engine warm up for ten minutes prior to driving and never had any problems. This morning, it had the hesitation several times at multiple speeds throughout the drive. This was the first time it's done this at any point after the first five minutes of drive time, so it seems to just be getting worse.

Any other suggestions before I take this to the dealership?

 

[QUOTE=RedRiderZR1;1597093356]I put in the Information on this code as well as the schematic for the MAF sensor. It should help you track down the issue. Peobably a good idea to check the voltages at the connector.


DTC P0102
Circuit Description
The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal in order to provide the correct fuel delivery for a wide range of engine speeds and engine loads. A small quantity of air entering the engine indicates a deceleration, or an idle. A large quantity of air entering the engine indicates an acceleration, or a high load situation. The MAF sensor has an ignition 1 voltage circuit, a ground circuit, and a signal circuit. The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on the inlet air flow through the sensor bore. The frequency will vary within a range of around 2,000 Hertz at idle, to about 12,000 Hertz at the maximum engine load. DTC P0102 will set if the PCM detects a frequency signal lower than the possible range of a normally operating MAF sensor.

Conditions for Running the DTC
The engine is running for greater than 0.5 second.
The engine speed is at least 300 RPM.
The ignition 1 signal is at least 8 volts.
Conditions for Setting the DTC
The MAF sensor frequency signal is less than 10 Hz.
The above condition is present for greater than 1.2 seconds.
Action Taken When the DTC Sets
The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
Diagnostic Aids
Inspect for the following conditions:

A misrouted harness. Inspect the MAF sensor harness in order to ensure that it is not routed too close to the following sensors or components:
The ignition coils
Any solenoids
Any relays
Any motors
A low minimum air rate may cause this DTC to set during deceleration. Inspect for the following conditions:
A plugged or collapsed intake air duct or a dirty air filter element
Objects blocking the MAF sensor air inlet screen
Throttle bore and throttle plate deposits
A wide open throttle (WOT) acceleration from a stop should cause the MAF display on a scan tool to increase from about 4-7 g/s at idle to about 190 g/s or more at the time of the 1-2 shift. If not, inspect for a restriction.
Any unmetered air entering the engine may cause this DTC to set. Inspect for vacuum leaks anywhere downstream of the MAF sensor.
If you suspect the vehicle condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Wiring Systems.

If an intermittent exists, refer to Intermittent Conditions .

Test Description
The numbers below refer to the step numbers on the diagnostic table.

This step verifies the signal circuit from the MAF sensor electrical connector to the PCM. A voltage reading of less than 4 volts or greater than 6 volts indicates a malfunction in the wiring or a poor connection.

This step tests the signal circuit of the MAF sensor for a short to another 5 volt reference circuit.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Install a scan tool.
Start the engine.
With a scan tool, observe the MAF sensor frequency parameter.
Does the scan tool indicate that the MAF sensor frequency is less than the specified value?

10 Hz

Go to Step 4

Go to Step 3

3

Observe the Freeze Frame/Failure Records for this DTC.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records that you observed.
Does the DTC fail this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4

Inspect the fuse that supplies the Ignition 1 voltage circuit of the MAF sensor. Refer to Engine Controls Schematics .

Is the fuse open?

--

Go to Step 14

Go to Step 5

5

Turn OFF the ignition.
Disconnect the MAF sensor harness connector.
Turn ON the ignition, with the engine OFF.
Measure the voltage from the signal circuit of the MAF sensor to a good ground. Refer to Circuit Testing in Wiring Systems.
Does the voltage measure near the specified value?

5 V

Go to Step 6

Go to Step 8

6

Connect a 3-amp fused jumper wire between the signal circuit of the MAF sensor and a good ground. Refer to Circuit Testing in Wiring Systems.
Start the engine.
Do any additional DTCs set?

--

Go to Step 16

Go to Step 7

7

Turn OFF the ignition.
Connect a test lamp between the Ignition 1 voltage circuit of the MAF sensor and the ground circuit of the MAF sensor. Refer to Circuit Testing in Wiring Systems.
Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?

--

Go to Step 18

Go to Step 11

8

Does the voltage measure less than the specified value?

4.5 V

Go to Step 10

Go to Step 9

9


important
Disconnecting the PCM connectors may eliminate the short to voltage if the signal circuit is shorted to another PCM circuit. Refer to Circuit Testing in Wiring Systems.

Turn OFF the ignition.
Disconnect the PCM. Refer to Powertrain Control Module (PCM) Replacement
Turn ON the ignition, with the engine OFF.
Measure the voltage from the signal circuit of the MAF sensor to a good ground.
Does the voltage measure near the specified value?

0 V

Go to Step 12

Go to Step 15

10

Turn OFF the ignition.
Disconnect the PCM. Refer to Powertrain Control Module (PCM) Replacement
Test the signal circuit between the PCM and the MAF sensor for the following conditions:
A high resistance or an open
A short to ground
A short to the ground circuit of the MAF sensor-- Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

--

Go to Step 22

Go to Step 12

11

Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and a good ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

--

Go to Step 13

Go to Step 14

12

Test for continuity at the harness connector of the PCM from the signal circuit of the MAF sensor to all other circuits at both PCM connectors. Refer to Circuit Testing in Wiring Systems.

Does the DMM indicate continuity between any other circuit?

--

Go to Step 17

Go to Step 19

13

Repair the high resistance or an open in the ground circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 22

--

14


Important
The ignition 1 voltage circuit of the MAF sensor is spliced to other components on the vehicle.

Repair the short to ground or an open in the ignition 1 voltage circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.
Replace the fuse if necessary.
Did you complete the repair?

--

Go to Step 22

Go to Step 20

15

Repair the short to voltage in the signal circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 22

--

16

Repair the short between the signal circuit of the MAF sensor and the circuit for which the DTC set. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 22

--

17

Repair the circuits that are shorted together. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 22

--

18

Inspect for poor connections at the harness connector of the MAF sensor. Refer to Testing for Intermittent and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 20

19

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 21

20

Replace the MAF sensor. Refer to Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement

Did you complete the replacement?

--

Go to Step 22

--

21

Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement

Did you complete the replacement?

--

Go to Step 22

--

22

Use the scan tool in order to clear the DTCs.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC run, and pass?

--

Go to Step 23

Go to Step 2

23

With a scan tool, observe the stored information in Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK



[/