rough idle

[b2thxtrm3]

1992 Vette. When I am sitting at a stop light the engine seems to idle a little rough. Then I notice that the lights in the radio and dash flicker. I start to thing that the engine is just gonna shut off but it never has. Is this a feul problem or electrical? :confused

 

[redc4corvette]

Check the fuel presure Lt1 43.5 psi.
The lights diming is the low idle.

 

[SSTibet]

Check fuel quality... That's where I would start from. I had a similar problem that went away after changing to a different fuel station. I also use injector cleaning fluid from time to time.

 

[Tuna]

This could be a sign of a dirty throttle body and Idle Air Circuit (IAC) also. Try cleaning the TB with one of the available spray cleaners paying some attention to the IAC area.

You might also want to put a good fuel system cleaner in the tank (I use Red Line or BG 44K) just to clean up the injectors and other fuel system components.

 

[Vettefan87]

The fuel system cleaner that Ken recommends, and is to be one of the best ones out there is Chevron with Techron. It is around 6 bucks a bottle and Auto Zone or Walmart should have some.

 

[Hib Halverson]

1992 Vette. When I am sitting at a stop light the engine seems to idle a little rough. Then I notice that the lights in the radio and dash flicker. I start to thing that the engine is just gonna shut off but it never has. Is this a feul problem or electrical? :confused

It's a little difficult to diagnose by Internet with so little infor but.

Idle stability can be affected by many things.

Check for vacuum leaks.
Make sure the ign. system is in good condition.
Run the fuel pressure checks in the Service Manual looking for leaking injectors.
Check the throttle body for bore and blade cleaness.
Check the engine controls harness goround.

If the idle roughness also causes idle speed to drop significantly, the lights flickering might be due to that. If the roughness comes with no idle speed drop, start looking or a problem with bad grounds.

 

[My Prozac]

I would start at the battery and alternator, then go to the fuel filter. You may want to pour in a bottle of dry gas. With other cars I have had they all seem to act funny when the eletrical system is acting up the cars require so much power just to idle, I had one car when the battery started to go the power window went up and down on their own, the wipers would move on their own, the radio turned on and off.. I thought it was possesed.

 

[Achilles]

I thought my rough idle problem on my '86 was due to a dirty TB or IAC, but found out yesterday that the butterfly shaft on the TB has wallowed out the body and the TB is sucking air through the gaps. Haven't torn into it yet to see if this is a fix-it or replacement issue.