98 Malibu Rough Idle

[pint4]

When I am driving my 98 MALIBU, the car idles rough when in gear. I put it in neutral or in park and the idle smooths out. What causes this?
Thanks.
Bob

[bcopeland]

From what I have been told, that is a common problem caused by the camshaft. What I would try is to a) shock the fuel system with some fuel injector cleaner (using 10 times the normal amout) and 2) cleaning the throttle plate with throttle plate - not fuel injector, cleaner.

That might work.

[wade623]

mine idles rough because of a misfire