Turboprincess

The idle on this 1997 will dip temporarily down to 200 and pop back up just as the car is coming to a full stop only while the car is in drive. The car idles perfectly in neutral no matter how I tap the gas pedal. If I put the car in neutral just before I stop, the idle does not dip. This seems like a transmission problem. Does anyone have an idea of how this might be fixed? I don't think it's the idle air stabilizer as it would just as likely seize up when in neutral. This problem is most likely to occur for about ten minutes after coming off the highway. Help?

zain

But I don't know why...

Mike AM

I never seen mine do that. I have a '97 1.8T automatic also. I'll check again today. I do have a strange bucking between 1500 and 2000 rpm. I'm bringing it to the dealer tommorow for that.

RPF

Use the Search Forums feature and search for IAC or idle air control valve.

performance tech

idle air control moter sticking,have throttle bore cleaned and idle air control motor cleaned may be carboned up,might need replacment but i doubt it

Dan F.

Tip delays downshift to 1st until the car completely stops for smoothness, and it seems like the car doesn't quite have the torque to hang onto 2nd at very slow speeds. So when it tries, the RPM drops almost down into the stall zone (but I don't think mine makes it all the way down to 200; maybe more like 400).

Dan

turboprincess

Have you ever seen the cause of the problem being the IAC valve when the symptoms only occur when the car is in drive and about to stop? It might indeed be the source of the problem, but I'm still wondering why the idle is always so perfect when the car is in neutral?

Bob Petruska

The engine is braking the car during the coasting. Just before it goes into its idle mode the ECU tries to compsensate for idle speed drop using the IAC and it can't because it's carboned up and reacts slowly. The IAC on a 2.8 is a bear to take off yourself. I did and cleaned it first with 2 plus 2 carb cleaner and then lubed with WD40. No problems in 1.5 years since I did that. I also have a '97 and would watch the idle drop to almost zero and then back to normal at almost every light I stopped at until I cleaned the IAC!

I'm 99.9% sure that cleaning the IAC will solve your problem. If you take it to a dealer they will change you for a new one, about $300 plus labor. Try to find someone who will clean/lube it for you first...then go the dealer route if unsuccessful!

DK

where's it located on the 1.8t?, Thanks

Bob Petruska

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