Very high idle!?!?

When I let off the gas the car maintains it's current RPM or sometimes even raises it while in neutral and foot off the pedal. Any ideas?

Thanks

 

[SouthCaliVR4]

If you still have the cruise control set up it can bind. Throttle cable inner liner can move & cause the throttle to hold open, throttle cable may just be binding. make sure the throttle body butterfly can move freely & that it's return spring is intact & of course that the pedal itself is not getting caught in a floor mat or some such. also check for vacuum leaks.

 

Stuck throttle plate, or sticking cable, large air leak, but some more info would help.

 

[FlyingEagle]

Idle Stop Switch might not be grounding showing the ECU that you have let off the throttle and are now at throttle closed position.

 

Quoting galant1517:
Stuck throttle plate, or sticking cable, large air leak, but some more info would help.


Well it is very random when it happens. When i let off it sometimes does not even reduce engine speed. It will idle very high at around 4000 and i cant get it to stop at times. When its in gear and under load its fine but as soon as i let off it or put it in neutral it will happen.

 

Its toyotas fault, now their unintended stuck throttle is beginning to affect old Mitsus. Damn you Toyota!

 

ttt

 

[trunks]

Maybe your isc is on its way out /ubbthreads/images/graemlins/dunno.gif.

 

[raptorWagon]

Could be the Throttle Position Switch on the side of the throttle body acting up, though I had a similar situation that started happening when I had a coolant leak and the temp would start to climb, in stop and go traffic.

If you put a load on the engine, do the rpms drop back to normal, such as turning your AC on? Or giving the gas pedal a small rev help it at all to drop down?

It may be a coolant leak or the tstat went out and stuck closed. As odd as that sounds, compared to the other ideas, that's was the reason my car had the same symptoms. My leak though was around the tstat housing to the head.

I also still had all the Cruise control crap on the car during that time as well.

 

Well the car is not overheating, however, the other day coolant was pouring out of the overflow. I have since put in water wetter and that has not been an issue.

I have not tried turning on the AC when it happens, but when you put it back in gear and start to drive again it goes right back to how it should be. Giving it a small rev does nothing.

I have another good throttle body with all good sensors. If it is the throttle postion switch acting up would a new throttle body correct that?

Thanks for all the info guys.

 

[FlyingEagle]

The idle stop switch is just a ground, whereby a single wire and connector attach at the back/top of the TB.
Check to make sure you have a complete circuit there when the switch closes.
Check over the bits mentioned above, because they could certainly be related to your problem.

 

Is it possible that my EGR valve is no good?

 

Problem solved, ended up being the throttle cable was way to tight.

Thanks for the help guys.

 

[vtecds1]

Is there a specific amount of slack the cable should have?

 

Not a specific amount, each car will act differently to that. Made mine to where you have to lift just a little bit before it opens th butterfly.