WHat the HECK @)^@%^#$$#

1990 xj 4.0
sunofa *(^*& when i start it ,it revs way up and i cant get it to idle.
this happened all of a sudden with no apparrent reason.

I cannot find any vacum leaks anywhere!!!

Any Ideas???


thanks in advance

TPS gone bad?

exuse me for being stupid, but what is a TPS?

TPS = Throttle Position Sensor.

I'd also dismount the IAC (= Idle Air Controller, little cannister on the front of the throttle body) and make sure that passage and the pintle are clean, and probably think about changing the IAC. It's a "pintle and seat" arrangement (like a fuel injector) that regulates the idle air with the throttle valve closed - if it's fully retracted, you're going to race at idle.

Might as well make sure nothing is binding the throttle linkage open - if the throttle valve is open...

5-90

bob mac said:

exuse me for being stupid, but what is a TPS?

Click to expand...

The TPS is the throttle position sensor.

It is more likely to be the Idle Air Controller, or your linkage is bound up causing the butterfly to not close all the way?

also there is a small allen head screw on the front botom of the throtle body that you can screw in or out to adjust idle it may have rattled lose and moved up thus causing it to hold rpms up like that if you look at the throtle linkage and then just under it is where the screw should be i had this happne on my 94...the screw pushes up on the throtle linkage....

Retorque the intake/exhaust manifold bolts. My bet is either the intake/exhaust gasket took a vacation or the gasket below the TB.

I have seen a vacuum booster do the same thing. Pull it and plug it to test.