idle poor when stopped

03-04-2007, 06:38 AM
I have a 91 prizm..When stopped at a light it vibrates, I put it in netrual and it stops..any one have an Idea what it could be?????????

03-04-2007, 04:15 PM
A vacuum leak would cause that -- check the vacuum hoses at and around the throttle body and intake manifold, making sure they're all connected -- if you don't see anything listen for a hissing sound in the engine bay at idle. There should be an "emission hose" routing digagram underneath the hood or somewhere in the engine bay that may help you.

04-18-2007, 05:11 AM
What is vibrating, the engine or something else? Mine the RPM gets so low it shudders the steering wheel sometimes. You might just need to adjust the idle RPM. Get a manual from the library.

06-16-2007, 09:00 AM
well it sounds to me like you may have a broken motor mount...since it stops when you put it in nuetral it may be the tranny mount...have those looked at or do it yourself...its is easy to detect

06-21-2007, 08:34 PM
DAM! I think I got your car. Just kidding. I just bought a 91 Geo. Has the same problem. Found the hose from the air filer box to the intake was loose around the intake. After taking care of that it is still doing it. I can still hear some kind of vacum leak, but having a hard time locating it. Haybne manual not much help. Shows other models but not mine.

Did you locate your leak ?

Mine is also has a hard time shifting into OD untill car is warmed up.

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