Diagnosing Rough Idle

[steppinthrax]

Ok this is the deal. I have a 99 Camry with about 30K on it. I just bought it last week. I notice when the car is at idle the RPM needle vibrates a bit at idling RPMS in response to the engine's rough idle. You can't really feel it because the car dampens it a lot but you can feel it in the brake pedal as well as see it on the RPM needle that shakes.

I changed all 4 spark plugs and the situation seemed to impove a bit. But in this case the rough idle is intermitent. Sometimes when at a stop the neelde shakes and sometimes it dosen't. This is with the new spark plugs. So I'm trying to find out what else needs to be checked/changed. I don't just want to keep changing parts.

[kpszar]

I had the same problem. I really did not seen it as a threat. Is it when the is warmed up and started agian. I think its pretty normal from a cold start. I hope its not your water pump because mine been replaced after the problem. I may not be correct. Any one can add?

[Eye8Pussies]

check for vacuum leaks- they are most apparent at idle and makes the rpms fluctuate and the car shake