C4 General Discussion General C4 Corvette Discussion not covered in Tech

Engine running bad

Thread Tools
 
Search this Thread
 
Old Oct 23, 2008 | 08:56 AM
  #1  
clthom2's Avatar
clthom2
Thread Starter
Heel & Toe
10 Year Member
 
Joined: Oct 2005
Posts: 24
Likes: 0
Default Engine running bad

Issues, Issues. Three weeks ago I drove my car downtown for dinner. It was about a 30 minute trip. I went in to eat. An hour later I was done. I drove my car down the street and it started running very bad, skipping. It wouldn't do more than 35 mph. I had it towed home. About a week later I started it and it idled fine. I drove it for about 15 minutes and returned home. I went in the house and came back out 10minutes later and drove the car. It started running bad and skipping again. Its really bizzare. Help!
Reply
Old Oct 23, 2008 | 09:03 AM
  #2  
clthom2's Avatar
clthom2
Thread Starter
Heel & Toe
10 Year Member
 
Joined: Oct 2005
Posts: 24
Likes: 0
Default

Oh yeah, My car is a 1990 with 54K original miles.
Reply
Old Oct 23, 2008 | 09:17 AM
  #3  
American Raven's Avatar
American Raven
C3 Corvette Enthusiast
Supporting Lifetime
15 Year Member
Liked
Loved
 
Joined: May 2008
Posts: 1,071
Likes: 3
Default

Is your car throwing any codes?

If not, have you changed the fuel filter recently?

Those are the quick things that come to mind.

At least it doesn't have an OptiSpark, so I'm thinking fuel flow. Bad fuel pump, partially clogged fuel filter, etc.

I'm sure other, way more experienced Vette-heads have experienced this. Give this thread a day and you'll have all sorts of info.
Reply
Old Oct 23, 2008 | 09:26 AM
  #4  
Randy93's Avatar
Randy93
Melting Slicks
 
Joined: Feb 2005
Posts: 2,135
Likes: 0
From: Sebastian Florida
St. Jude Donor '06
Default

What is skipping? Is the RPM hunting or is the engine miss firing?

If it only does it when hot, sounds like an ignition problem and like raven asked, is there any codes?
Reply
Old Oct 23, 2008 | 10:32 AM
  #5  
clthom2's Avatar
clthom2
Thread Starter
Heel & Toe
10 Year Member
 
Joined: Oct 2005
Posts: 24
Likes: 0
Default

I haven't checked any codes. The check engine light isn't on. I haven't changed the fuel filter in quite sometime. Also skipping is engine mis-fire.
Reply
Old Oct 23, 2008 | 10:44 AM
  #6  
All2kool's Avatar
All2kool
Drifting
15 Year Member
 
Joined: Oct 2006
Posts: 1,694
Likes: 0
From: Beaverton Oregon
Default

Originally Posted by clthom2
I haven't checked any codes. The check engine light isn't on. I haven't changed the fuel filter in quite sometime. Also skipping is engine mis-fire.
Check the MAF. Mine ran poorly, I cleaned the MAF, problem solved. Sometimes just disconnecting/reconnecting the MAF will help. You do have a MAF? Is the Distributor loose?
Reply
Old Oct 23, 2008 | 11:02 AM
  #7  
clthom2's Avatar
clthom2
Thread Starter
Heel & Toe
10 Year Member
 
Joined: Oct 2005
Posts: 24
Likes: 0
Default

Whats the MAF? Where is it located? I'm moderately engine savy. I can do a tuneup etc.
Reply
Old Oct 23, 2008 | 11:14 AM
  #8  
American Raven's Avatar
American Raven
C3 Corvette Enthusiast
Supporting Lifetime
15 Year Member
Liked
Loved
 
Joined: May 2008
Posts: 1,071
Likes: 3
Default

If you do any of your own wrenching, you really should have a code reader/scanner.

The Auto X-Ray EZ 2000 is what I have. I paid $199.00 for mine last year and it has paid for itself in reading codes. This reader is OBD I & II compliant so you can use it on any other car that uses OBD codes (all cars from 1996 forward are OBD II compliant).

You can now get a new one for $79.00. I wish I had this sweet deal last year.

http://tinyurl.com/6hcwhp

Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-1

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-2

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-3

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-4

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-5

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-6

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-7

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-8

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-9

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
Old Oct 23, 2008 | 11:36 AM
  #9  
clthom2's Avatar
clthom2
Thread Starter
Heel & Toe
10 Year Member
 
Joined: Oct 2005
Posts: 24
Likes: 0
Default

I have a code reader. I haven't used it in a few years. Wouldn've the engine light have to be on to have a error code?
Reply
Old Oct 23, 2008 | 11:41 AM
  #10  
JrRifleCoach's Avatar
JrRifleCoach
Team Owner
20 Year Member
Veteran: Navy
St. Jude 20 Year Donor
Liked
 
Joined: Sep 2003
Posts: 20,179
Likes: 673
From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Default

Originally Posted by clthom2
Wouldn've the engine light have to be on to have a error code?
Not necessarily. Check the codes.

The MAF is between the TB and air filter. When the engine starts running rough shut it down, unplug the wiring connector to the MAF and restart the engine. If the engine runs better, you can clean it (MAF) or troubleshoot the burnoff relay and power relay. Do a search on the subject. Lots of experience here to draw on.

Last edited by JrRifleCoach; Oct 23, 2008 at 11:44 AM.
Reply
Old Oct 23, 2008 | 12:19 PM
  #11  
clthom2's Avatar
clthom2
Thread Starter
Heel & Toe
10 Year Member
 
Joined: Oct 2005
Posts: 24
Likes: 0
Default

What does MAF stand for?
Reply
Old Oct 23, 2008 | 12:25 PM
  #12  
cmcbunch's Avatar
cmcbunch
Instructor
 
Joined: Jan 2008
Posts: 163
Likes: 1
From: Idianapolis Indiana
Default

Mass Air Flow sensor. It will be a round object inbetween the throttle body and the air filter. It measures how much air enters the engine so the ECM can calculate the proper ammount of fuel to maintain AF ratio.
Reply

Get notified of new replies

To Engine running bad





All times are GMT -4. The time now is 04:02 AM.

story-0
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-1
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-2
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-3
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-4
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-5
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-6
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-7
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-8
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-9
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE