7mge Idling Problems - Toyota Nation Forum : Toyota Car and Truck Forums

TS-R · 07-07-2009, 12:29 AM

I just Bought a 1989 Cressida with a supra 5 speed tranny. I figure more people look at supra's and it has the same engine.
Anyways I got this car for a good price but there is one problem.
The engine Pulsates between 1,000-3,000 Rpm's
When the TPS is adjusted it Idles at a steady 3,000 Rpm's
I have tryed a different TPS and it made no difference.
I also tryed turning the idle down all the way and made no difference it seemed to be all the way down when I got it.
I was wondering if it could be a vacuum leak? OR??
Thanks for any suggestions.

***bgrieger*** · 07-07-2009, 01:22 PM

Might be. Might also be the idle speed control valve being too gummed up to close, or the dashpot in the throttle body may be sticking.

Jeeves · 07-07-2009, 04:03 PM

I'd look at the idle speed valve wires. On my last install three wires broke, so instead of smoothly stepping it had giant steps and would pulse between them.