I have a 95 C4 automatic. I have the weirdest thing and will welcome any help.

Sometimes it wont start. It will crank and not catch. Sometimes it happens after its been sitting for a while. Sometimes it will just jerk, stall out while running and then not start again. I can go back to it HOURS later and it starts right up. I can be driving and it will act like it isnt getting any gas, the tach will bounce all over the place, then it will just stop running. I have to coast to safety and see if it will start again. Sometimes it will sometimes it wont. Last night when I was driving it, it started backfiring, acting like it wasnt getting any gas, acted like it wanted to stall, it didnt and then it was fine. I was on the freeway when this happened and it was scary.

I have replaced the water pump because it went out. Then it started acting like this and I had to replace the entire distributor assembly twice because the first one was bad, The transmission is new. I had a missing hose clamp on the intake and replaced it because the code on the comp. told me the mass airflow sensor was getting bad readings. Still it wont run properly. It will just stall out and die intermittently. I love my car and I dont wanna get rid of it but I am at my wits end!

Has anyone had anything like this happen? I need help.

 

Your issue sounds fairly common and there are fixes for it. The problem is,,,there are a few things that it could be. You need to read and post the DTcs that the PCm is throwing so we can zro in on the exact area that causing the issue.

Heres how:

READING YOUR Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.

The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each module. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.

There are two types of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes. More likely it's an indication of an intermittent malfunction.

Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.

Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.

You can read the DTCs while the engine is running. If you turn the engine OFF and then back ON, that can clear some DTCs that may be important with identifying a problem. One example is a Misfire DTC (p-0300) If the engine is shut down, the DTC will clear.

These are some very good C5 Diagnostic Trouble Code (DTC) explanation web sites!!! They also explain how to read the DTCs

Here are some very good sites that explain what DTC mean:

http://www.gearchatter.com/viewtopic11755.php

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix when you post your DTCs!!



IF,,,you have a TON of DTCs, you can clear ALL of them and see what comes back. thats the best data.

Post the DTCs and lets get your car fixed!

BC

 

You mistakenly have posted in the wrong C section.

But that's no problem.

You've got the best man for the job. If Bill can't fix it nobody can.

 

very good advice but he has a 1995 C4. he will need a paperclip to ground pins in the adl to get his dtc's. 1995 is odbii 16 pin connector with odbi codes. search the C4 tech section for instructions.