Rough Idle

ASSISTANCE Stock Engine-Bay Components
1

Basicly when my car is in drive it idles very rough, to the
point where things shake in my car, so mostly I have
to drop the car into netural to stop the vibration.

There is no CEL, I have tried adjusting the idle but had so
success with that. The car runs well when not stopped
and the gas milage is normal. The engine is stock.
I was thinking it could be some sort of sensor.
Any suggestions? thanks

I have searched through the treads, but didnt see my
exact problem.

2

Is the idle surging or does the car just vibrate at idle?

3

the rpms do bounce from low to very low.

4

me too :bang: …but sorry I still cant figure it out

Ive replaced wires, plugs, distributor cap and rotor, fuel filter, pcv valve, water pump, timing belt, valve cover gasket, fast idle valve, and adjusted the idle. Still shakes like a mofo and bogs occasionaly, but she runs great on the highway. :shrug:

5

i had a thought maybe it could be one of the motor mounts.dont know just a thought

6

Anyone have any solutions to this?

I’m having the same exact problem, where the car idles very rough at stop lights and such, but idles just fine when in neutral or park. It seems to be a bit better in reverse, but not much. Since it only happens in gear, I am guessing it wouldn’t be related to something like a motor mount (since that would cause a rough idle even in park, right?). I actually have had an induction service and motor mounts were replaced in the past, and it didn’t seem to do anything for it.

I know my EGR valve is weak, but not causing the CEL to trip in most cases, even after long hours of driving. Could a bad EGR valve cause the idle problem? Any help is appreciated.

7

I replaced my EGR somewhat recently and it did not affect any idle problems. My EGR threw a CEL code when it went bad.

8

+1

9

usually a rough idle in gear but not in park or neutral is an indication of a vacuum leak, i would start there

10

If there was a vacuum leak, wouldn’t the engine rpm go up and down to try to compensate?

11

a small leak yes, a larger leak the iac cant compensate for if it goes to full count