Fast & Pulsing Idle

[clapton924]

Strange thing happened today. Started my car up, pulled out on the street and noticed the car was idling much faster than usual (around 2k). I could also feel the rpm's pulsing up and down with my foot off the gas. I pulled into a parking lot and turned the car off. Turned back on, idled around 1500rpm...then suddenly dropped to 700 and the RPM dial began to pulse between 700 and 1200....At this point the engine light came on. I turned the car off and waited a few minutes. Started back up....the rpms seemed to calm down....I went on to the store with no real problems. The car seems OK now but still feels a little "off" for lack of better words. I will get the ECU code tomorrow.

 

[Mike]

When you say pulsing does it feel like its trying to pull forward?

[clapton924]

When you say pulsing does it feel like its trying to pull forward?

A slight pulling feeling, yes. But its because the RPM's are fluctuating.

[CrackerTeg]

The code would help us help you. In my old car, it was the fast idle valve that turned out to be bad. I'm not sure if our cars are equipped with such a valve but that's my previous experience with that problem.

[clapton924]

Yeah, I will get the code asap.  One of my friends who works on Japanese imports thinks it could be a vacuum leak. We shall see.

[timot_one]

You're getting a CEL?  If so, definitely try and get the code.  From your description, it sounds like your idle is surging.  Your friend and Z could be right.  It could be a vacuum leak or it could be something with your IACV.  I've experienced the surging idle with my car because of a vacuum leak and I've also seen it because of a bad IACV on someone else's car.

[Mike]

The code is def the key hear. I can tell you that at one point I experienced a fluctuation in RPM and when the RPMS dropped the car sort of lunged forward. This would only happen at a stop light while in gear. In my case it ended up being a bad torque converter. I never had a code though so it would really make me think yours is vacuum or sensor related.

[CrackerTeg]

I'm going to go out on a limb and say his IACV is the culprit. At least I know what the damn thing is called now.