Thread: Idle issue

I know its been done to death but i cant seem to diagnose mine. Ive done a exstensvie search here, the other site, nico and a cople others. No one seems to have the exact problem i have. Its my wifes 94 G20.

When you start it , it fires right up. Soon after i mean seconds its idleing hard like its got a big cam in it. I dont think its a injector issue because the car idles fine if you put in in neutral. It only does it when it is stopped waiting for a light, fast food drive thru or something. This weekend im going to change the plugs,wires, cap and rotor it needs it anyway. Im thinking of running some seafoam first before i do this.

Someone said it can be even a grouunding issue but unlikely to me since it idles fine when in neutral and runs great on the highway. The fuel mileage has not been hurt by this either. It still gets around 27mpg overall. It has a clean k/n drop in filter. The car also has 205k on it if that helps. Ill check the egr crap as well and the iacv this next weekend. Any other suggestions. Also this sounds like a noob question but where is the pcv valve on a lowport? Up by the vent hose on the back of the v/c? Thanks for the help in advance.

the vent hose on the back of the v/c is the pcv hose, yes. In a worst case scenario, I would check the torque converter, since you say it idles fine in neutral. Check the condition of the ATF. You say you're going to change the plugs, wires, cap and rotor; have you not done this in a while? If so, how long? Do you feel any misses when you're accelerating? That would be a reason to suspect the ignition system. Good luck and I hope all these questions help you find the culprit. Post up what you find and I'm sure there will be someone out there who has had the same symptoms as you that just hasn't posted it yet.

pull the pcv valve and shake it and see if you hear the ball move, if your dont its prolly stuck open or closed either or, spray it with some carb cleaner and see how that works, or just replace it they are cheap

Yeah thanks, im going out to check that today.

I posted a thread on this already. The auxilary bypass valve. Look for it. I am on my cell so I can't pull the link. It lead to my FedEx thread in offtopic. LOL.

My bad, did not realize this was not cold idle. I have this issue as well to a lesser degree, so I will check my PCV too.

Yea, her car idles like its got some big cams in it...but only during idle

Automatic?
torque converter is possible (as someone said) since it idles smooth in neutral. If its not studdering/hesitating and missing.

PCV valve, IACV valve, EGR system, Vacuum lines...just SOME ideas.

Tune up would help but Id think it would misfire or something while on the pedal if it idles that bad. Goodluck on the find