Rough, loping idle...

Kilgore Trout

Fried or Broiled ?
10 Year Member
Mar 30, 2005
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My Cobra idles rough.

So far I have tried:
-seafoam
-changed plugs
-cleaned MAF
-reset PCM

Is it normal for there to be a bit of roughness in the idle?

Other things I am planning to try are:
-new fuel filter
-new x-pipe because I think my cats are clogged

But maybe the lope is just normal for the engine??? :scratch:
 
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Well, I just recleaned the MAF and also cleaned the IAC plus I again reset the PCM.

The idle still sucks :(

Next up is a fuel filter, if that does not correct it I have a feeling it is gonna be something expensive to fix... $$$
 
Yes, the idle is exactly the same as it was before I started doing things to attempt to correct it. Nothing I have done has had any effect on the rough idle.

However, driving in to work this morning in the cold rain with the a/c on the idle was much smoother. Perhaps the fuel trims are re-learning to smooth it out. I will keep a close eye on it for the next few days.
 
My 99 has done the same thing since day 1. Slightly rough idle at about 750-800 rpm when warm. Idles smoothly about 850-900 when cold. Gets better for about 15 minutes after changing plugs then goes back to same old deal.

I occasionally wonder about an injector/coil issue. Doesn't seem to be generating any codes.