High Idle, please help!

[guillebeau5150]

I plan to read the codes tonite so ill post those when I get them. About the TPS though, I did an analog multimeter check and it was smooth all the way through, so it should be working fine shouldnt it? or could there be another issue with it?

Also should note that on cold start it revs to 2000 then slowly drops to about 1250. Once it gets on the road its 2000 rpms.

[Alex L]

I have a similar problem. It starts fine but after driving will maintain about 2000 rpm's just sometimes. I can stomp the throttle and get it to go back down sometimes. My throttle body linkage seems worn some and I can manually push the butterfly closed at the linkage and it slows back down.

good luck finding the exact metal linkage, but a later model ranger linkage will work (the plastic push on ones). the bushings wear out and cause the throttle plate to get sticky; a squirt of lube on the throttle shaft bushings will settle it down for a few months IME.

[kiwi]

IAC leaking inside..air getting past the piston.

[guillebeau5150]

I pulled the codes and got back 67, 10, and 63. I know 67 is throttle position below minimum voltage, and 63 was a clutch or neutral safety switch (worry about that later) but Im not sure what 10 is. I checked all voltage with tps and iac and it all checked out but Im sure theres more to it.

I know that the iac is the cause of the high idle, whether its the wrong signal sent to it Im not sure, but Im starting to think like most are saying that its either stuck or just some how letting air slip through that shouldnt. I took it off and let it soak in cleaner tonite, so well see what happens tomorrow. If the same old same old, may be time for a new iac..

[guillebeau5150]

Okay, I have replaced the ect sensor, pcv valve, tried 3 different iac's one of those a brand new one, set base idle, checked the tps with analog meter and it checked out perfectly and it still gives the same problem, idling at 1500 rpms generally most of the time. Sometimes it takes warming up others it will start before Im out of the driveway in the morning. So today I disconnected the iac and have been driving it around and it idles at 750 perfectly, except on startup and when the air is on.

So, something is causing the iac to open up too much when its connected. What is causing this? Is there a misreading somewhere making the computer open it up to much? or is the computer simply faulty? Need advice on what to look for now, Ill but a new computer but really dont wanna spend that money to not fix it..

[kiwi]

still high?

Restrictor plate

[GAboySVO]

Perform this test:
1. plug the IAC back in
2. start and drive as normal until high rev issue starts
3. quickly switch the ignition off then back on
4. If the idle returns to normal, replace your TPS.
5. If it remains the same, check your wiring to the TPS and IAC

[guillebeau5150]

GAboy, I have done that many times, that was the only way to get the idle down. But if it was the tps why does it not rev high with iac unplugged?

[GAboySVO]

GAboy, I have done that many times, that was the only way to get the idle down. But if it was the tps why does it not rev high with iac unplugged?

Because you have removed the EEC's control of the IAC which compensates for the idle based on all of the sensor inputs plus engine load. The idle you are seeing with the IAC removed is base idle. When you plug in the IAC it recieves the signal from the EEC that the reference voltage has changed on the TPS input and adjust the IAC output to compensate.

[guillebeau5150]

new TPS did the trick! thanks guys! man that was a headache. Even though the old tps checked out fine with an analog meter it was still faulty. I presume as gaboy said the old tps was sending incorrect data causing the iac to open up way too much.

Man, I love driving this car again.

[GAboySVO]

Glad to here you fixed it.