My LT1 has just over 70,000 miles on it and other than minor mods has not been toutched. The car starts great never misses a beat, runs great and goes great when you put her to the floor but it has a rough idle. I cant for the life of me figure it out. I have done the normal maintance things like plugs and wires and fuel filter ext. but it still idles rough. Is this normal for the LT1 to idle rough? Or is there some other maintance itrem that I am missing?

Brian

 

Is this a new development or something you've been trying to track down for a while?

"Rough" is very subjective... it's been so long since my LT1 was stock I don't even remember what it idled like, the whole car shakes as it is now If it makes the power it should and gets good gas milage you probably don't have a problem. You could clean the MAF and check for any leaks after the MAF such as a small tear in the intake elbow. Are there any ignition shorts when you look under the hood in the dark? An opti could possibly cause this as well but usually deteriorates rather rapidly also. If you have a ported MAF that could very well be part of the problem.

Really, if everything else is running fine and it has always done this it's probably your imagination. My brother thinks his '02 WS6 has a rough idle too but it's running normal.

 

Check your motor mounts. A broken mount can cause the engine to shake and appear to have a rough idle.

 

try cleaning your iac. i cleaned my iac, throttle body, and egr valve and the car ran and idled much better.

 

I guess the car has idled rough since I got it or atleast since I can remember. I will start with the motor mounts and the IAC/throttle body cleaning. Thanks

 

i had a rough idle and suspected one of my O2 sensors for the longest time...finally it died and so did my rough idle once i replace the sensor.

 

Maybe it's the Minnesota air, I think mine idles rough too.

 

I think you are right!