I guess I'm not really on board with a vacuum leak causing a hunting idle. A leak usually leads to elevated engine speed but not the oscillating one.

My guess would be that the IAC is trying to compensate for something else......a bad TPS comes to mind.

The best way to figure this out is to use a scanner to see what the computer is seeing and doing. If you don't have a scanner you can download TTS data master and buy a cable...you'll be set to run logging scans.

I have seen something like this with fouled plugs. However,that was a case of the idle starting low and going lower....

 

ALL THE HOSES.....are good no leaks i researched and found out a vacuum l eak doesn't cause high idle,if i had a vacuum leak id lose power have poor acceleration stumbling,i dont have none of that,im leaning to the spark plugs its been 4 years since i changed them.

 

A small vacuum leak will cause a high idle regardless of what your research found....

Checking the plugs is a good idea. So would replacing the wires if they're old....

 

I think i didn't explain it right guys the idling isnt high it goes goes to 1100 to the most 12 or 13, but my engine isn't running rough it just sounds like sum1 is pushing the gas when it idles up,i checked every vacuum hose like joe said all are fine.maybe shoebox or Fred can can fix this

 

Perhaps they can....but you can make their diagnosis a bit easier by running a scan and looking at what the heck is going on with the TPS, the fuel trims, the IAC, etc.

 

Yea u got a point there all im gonna do is do a tune up and see wat happens

 

Plugs, wires, filters, etc. won't cause a high idle to magically go back down.

A scan will be infinitely more helpful than a "tune-up."

 

Joe speaking of scanning i have an engine light on it only cones on a few seconds after the car is running. the idling is way better now,not idling so high no more. But the obd1 scanner i have i followed all the directions i connected it entered the data it asked,turned the ignition on,then it says the vehicle isn't responding,i even took it to a shop n they couldn't even pull the codes on their diagnostic

 

Hey guys i have the results to the diagnosis
1.the egr valve isnt opening
2.the map sensor is at 2.41 volts should be at least at 5
3.the tps sensor is @ 1.24 n should be close to 1.33
4.the knock sensor is malfunctioning becuz the tps isnt adjusted to the correctly

Now guys my buddy told me to start with the egr valve do i change the egr valve or the egr vacuum solenoid. Bc i dont throw parts n waste money.

 

the EGR doesn't open at idle...and it isn't supposed to. You really should post exactly what the scanner said....complete with codes....for anyone to be able to help.

 

Under what conditions did you get the sensor measurements posted? With the throttle closed, for example, the TPS should read between 0.20 - 0.90V. Anything outside those limits will set a code.

The MAP sensor reference voltage is 5.0V. When you turn the key on, but don't start the engine, the MAP sensor will read baormetric pressure, giving a voltage of 4.5 - 5.0V, depending on the elevation where you live. At idle, you would see about 1.2 -1.4V. But depends on how much vacuum the engine is pulling.

The knock sensor does not work incorrectly because of TPS voltage. The PCM simply checks the voltage on the knock sensor circuit to make sure it's between 1.5 - 3.5V.

 

That is wat the scanner said the key was turned on but the engine wasn't running and i did tell u what the scanner said so dont u tell me i didnt.i was born and raised in the u.s.a. so im not an idiot

 

Is it time to close this thread? There is no need for an outburst like that.

 

I apologize for the outburst guys but how can i start with the issue the egr valve does seem fine im not having symptoms of it beijg bad

 

Can you tell us the code that the scanner gave you? The problem is that most scanners use generic language and not LT1 specific information. The codes will help us sort this out.

If there are no codes, post that as well.

What I think would really help is if you could get a logging scan done. That would show what is going on in real time and not a point in time that the regular scanners show. If a logging scanner is not available to you, all you need is a laptop and a cable...there is software that can be downloaded.