[jhoagg]

I have read the posts on rough idle problems on 3.2 L engines (and the fixes), but wonder if this is different. Engine has around 100K. Starts right up, and proceeds to idle extremely extremely roughly (both warm and cold). Warm idle is right around 800. When run up above idle it seems OK, and seems to pull strong up the rpm range when the car is driven. No stumbling or other bad stuff.

Would you suspect a top end problem like busted head stud, burnt valve or other even though it runs much better at higher rpms? Is a really terrible idle symptomatic of top end problems? I am thinking a leak down test is indicated, and a look for a loose head stud.

Here's the little I know:

1) It's firing on all 6 cyls. The plugs have been in quite a while, and all look like very normal wear (no dry or wet fouling, etc) - except the center insulator on one plug which is still quite white, instead of the tan/grey color of all the others. But the rest of that plug looks like all the others with normal wear and color.

2) Pulling off the oil cap decreases rpm as expected and makes the idle even worse.

3) No question it has been a long time since this engine had a new fuel filter, valve adjustment, retorque of manifold studs, etc, etc.