Rough idle--opinions?
Thread Starter
Burning Brakes
Joined: Feb 1999
Posts: 1,157
Likes: 3
From: Encino CA
Rough idle--opinions?
I have a 95 LT-1 that has generally been running great. I have suddenly developed a rough idle at a stop in gear. My impression is that it is not electrical (it feels different to missing I have had in the past due to bad plugs or wires). The car starts fine and runs fine and the idle is fine until after the car warms up. What happens then is a regular roughness at a stop, like while waiting at a light. The unusual thing is that when this is happening, the slightest touch on the gas pedal will result in the car really lunging on the takeoff. If I stop only briefly, the response from the gas pedal is normal. It is only after idling for a minute or so that the pedal seems unusually responsive.
My own thought about this is that the engine is getting too much gas at idle and the addition of air by touching the gas pedal results in the lunge.
Are there some clever diagnosticians out there who have a better idea of what is happening and why before I bring the car to the mechanic?
Thanks,
Doug
My own thought about this is that the engine is getting too much gas at idle and the addition of air by touching the gas pedal results in the lunge.
Are there some clever diagnosticians out there who have a better idea of what is happening and why before I bring the car to the mechanic?
Thanks,
Doug
Thread Starter
Burning Brakes
Joined: Feb 1999
Posts: 1,157
Likes: 3
From: Encino CA
I checked for codes using the paper clip method and found none. This was no surprise as there have been times in the past where the car was running horribly (due to shorting spark plug wire or something else) and no codes were thrown. It seems that there has to be something really catastrophic for the computer to finally throw a code.
Doug
Doug
Thread Starter
Burning Brakes
Joined: Feb 1999
Posts: 1,157
Likes: 3
From: Encino CA
Doug
Safety Car
Joined: Dec 2007
Posts: 3,616
Likes: 5
From: Sandhills of North Carolina
I had a similiar problem when I got my vette back in Nov. I think the previous owner had been running a low octane fuel. Exhaust tips were black. I ran a couple of cans of Seafoam through it (I'll get slammed for that, I'm sure) At 2000 mile intervails on a full tank with each one. That helped a lot. I disconnected the battery to reset the codes a couple of times since Nov. That also seemed to help. The biggest help was cleaning out the mouth of the TB. Get back in there as far as you can. That made a huge difference in the way it idled.
Thread Starter
Burning Brakes
Joined: Feb 1999
Posts: 1,157
Likes: 3
From: Encino CA
I should have mentioned that the missing started after adding some PurEscape into the gas. I had done this before and was pleased with the results the first time. Also, I only added 1/2 the bottle. Nevertheless, it seems too much of a coincidence that the missing started when the PurEscape was added.
Doug
Doug
