944.0

I have cleaned my iac and tps. Started it and it idled at about 1000 rpms. Took it for a short drive and when I got back it was idling at about 1500. Unhook the map sensor vacuum and it drops. Checked for vacuum leaks and couldn't find any. What else should I look at?

cashmoney11

Maybe your cruise control cable is pulling on the throttle body a tad.

bighouts5591

Reset your ECU, the tps could be thrown off because its clean now

ZINGGG

How exactly did you clean your TPS?

944.0

I just took it off and sprayed with throttle body cleaner. There really isn't anything to clean, I know.

ZINGGG

There's a way you can test the TPS. I don't have the write up but it has been posted many times. Search for it and do that. You may have damaged it even worse if it was already faulty by spraying it with TB cleaner.

And did you clean the throttle body as well? And put on a new TB gasket? Then torque the bolts correctly? Do that if you haven't yet.

bighouts5591

Seriously try resetting your ECU before you do anything else, its free

ZINGGG

Yes you should definitely do that.

And adjust your throttle valve cable

944.0

Yes I cleaned the throttle body. I didn't replace the gasket because it was good still. I don't have my chiltons handy so I don't know what the proper torque for the tb is. I have a digital multimeter so I don't know if that will work for the tps test.

944.0

And what's the procedure for resetting the ecu? Something like holding the battery connectors together for 30 seconds then something with the headlight switch?

ZINGGG

Disconnect the Positive battery terminal and touch it to ground for 30 seconds
Reconnect the battery terminal
Turn key in ignition to ON position (withOUT starting it up)
Turn headlights on
Turn headlights off
Turn key to off position
Then start her on up (and reset radio presets, etc)

flexin91xj

I had the same problem with both of my '91s and it always turned out to be a vacuum leak or loose vacuum connection. Alot of those vacuum hoses can get brittle and crack over time. If its getting worse after the engine warms up then I would guess its a small crack in a vacuum line that is expanding when it gets warm.

ZINGGG

^this is also a great possibility

You should also retorque all bolts on both exhaust and intake manifolds. That can cause a vacuum leak and a messed up idle.

944.0

That seemed to help. When I start it it shoots up to about 1900 rpm then settles at around 1000 rpm.

ZINGGG

Yeah something else is the problem. Take the above suggestions and put em to good use!