95 Geo Idles wide open!

[BoneYardCustoms]

My car is on crack!

Hey guys, I've dug through the forum and this isn't the first time this problem has been posted but I haven't been able to find any of them that have what the resolution was so I am hoping you guys can help. I have a 95 geo with a 4 cylinder, with a/c and 105k miles and it has been running great. A couple of days ago we started it and instead of idleing it was like someone floored it and the car idles wide open until you shut it down.

I have checked the hoses for a vaccum leak and they all looked like they were good. I checked throttle cable to see if it is sticking and it's loose and the butterfly is almost completely closed. I also checked the idle speed control motor and it doesn't seem to be interfereing. I haven't completely ruled out a vaccum leak but seems odd for that to be the issue because of how high it is running. I ordered a TPS sensor (back order) and pulled the throttle body but I'm hoping not to dump too much money into parts that don't need to be replaced.

Any assistance would be appreciated.

Thanks,
Shawn

[doug2060]

I don't expect this to help but I'll put it out there. When I read your post it reminded me of an issue I had with one of my first cars. I had a real old Pontiac Fiero. I came out one day and started it up and it went crazy. It was like it was floored. I could'nt find the problem until my step dad started it up with me looking at the throttle. The cruise control had malfunctioned and was kicking in full blast. If your metro has cruise control (mine doesn't) its worth looking at. Is there a check engine light on?

[91Caprice9c1]

A sensor malfunction alone cannot do what you are describing. For the RPMs to rise that high, there HAS to be air escaping into the engine from somewhere other than the throttle body. In a case like this where a vacuum leak has not been detected, and with the amount of air seeping in, I would have a very close look at the brake booster as a possible culprit.

-MechanicMatt

[doug2060]

Try looking all around the throttle body and intake manifold too. There may be a hose loose in the back or hiding where you can't see it.

[Johnny Mullet]

Make sure the throttle body butterfly is not loose also.