Fast idle issue with 91 n/a - Toyota Nation Forum : Toyota Car and Truck Forums

hunterone1 · 08-30-2007, 05:53 PM

I have a 91 mr2 n/a that I am having a fast idle issue with. When I pull to a stop, it idles at about 2000 rpm. If I tap the gas pedal, it drops to normal. Does it about 50% of the times I stop. I have cleaned the linkage, and had a mechanic clean the linkage to no avail.
I took to my local Toyota dealership, and they ran diagnostics and said it was a vacuum nipple on the fuel surge tank. They said they couldn't find the part anywhere in the US!! They cleaned it up and that helped some, but didn't fix the issue. They gave me 2 part numbers, 90917-11023 (gas filter) and 25860-74050 (vacuum switch). I found both parts on the internet. Does either of these sound like they would fix my problem? I have no problem buying both, I just want it fixed!!

***MR2Jedi*** · 08-30-2007, 10:56 PM

Try cleaning the throttle body with carb/injector cleaner. If they get some deposits in there, it can make the butterfly in the throttle body stick alittle.

WT Morgan · 08-31-2007, 05:39 PM

Try to get it to occur while your are watching the throttle in the engine bay. (This is usually best to do with the lid open and the car at a stand-still

)

When it sticks, manually move the throttle body lever and see if it helps. See if you can tell if it is the cables. Lubricate the linkage friction points and cables (sounds like that was already done).

You can try pinching (the accused culprit) vacuum lines or unplugging them and test/retest to see if that is indeed whats causing the problem.

Don't forget the hidden simple stuff like your accelerator pedal, pedal linkage, carpeting, rubbing on the firewall, mechanical points that are dry or binding anywhere from the sole of your shoe to the buttefly valve in the throttle body.

I wouldn't order parts until I had done all of those things.

Good luck! Let us know what you find.

WT Morgan · 08-31-2007, 05:45 PM

I second MR2BADs suggestion! Also, the A/C is tied in and bumps up the idle when the A/C is on. You could have something going on there, but I haven't checked out that system. You could notice if it changes anything when you have the A/C on or off.