Idle holds @ 1500 RPM and RPM's surge between 1100-1500

[KO iNfAmOuS]

I have a video of the tach on my phone but it is dead. We think the surging is from a vacuum leak but now that it has stopped we have no idea. But when I started my car this afternoon it immediately went to 1500 RPM and stayed there. I drove around my entire campus without touching the gas pedal. Now it is driving normal, and we looked at it and scanned but no error codes came up. Only problem remaining is normal idle is 300-400 and is fluttering. I have no idea. Went from really high to dangerously low. Any ideas? Thanks for the help.

 

[ZsleepizeZ]

umm idle control valve?

 

[KO iNfAmOuS]

that was our second guess..the idle position sensor went bad?

 

[ZsleepizeZ]

idle position sensor? or throttle position sensor?
have you done any job that involved removing your intake manifold? if you havent then it is probably the idle control valve.

 

[HondaLuver83]

300-400 is very low at idle. Should be aroind 6-700 and 800 for 5 speed

 

[ZsleepizeZ]

its a five speeD v6?
nice..

 

[SN95GTMustang]

Sounds like you have an IAC problem. I would personally try removing it and cleaning it with a decarb cleaner. You can buy a can at any autoparts store. If that doesnt take care of it. Try checking for a vacuum leak with the same decarb spray, but do it on a cold engine dont want to risk a fire. I personally use a small amount of water because no risk of fire and accomplishes the same thing but you cant get messy with it or you dont know where the leak was. Anyway you can start by spraying suspect areas while the engine is running and the idle is up. If the idle suddenly drops when spraying a suspect area, there is your vacuum leak. If it doesnt change no matter where you spray then you probably dont have a vacuum leak and your back at the IAC or an input sensor to the PCM that is off effecting your idle.

 

[KO iNfAmOuS]

It's a v6 auto...got intake and exhaust that's it...intake extremely loud now and gray smoke from exhaust....I think I may be running too rich as well? Might explain only 160 miles on 25 dollars (2.79/gal)

 

[BadgerType]

try swapping out the o2 sensor

 

[KO iNfAmOuS]

would the o2 sensor cause it to surge? That would explain my horrible gas mileage since it would cause it to run rich and explain the gray smoke, and that also affects the throttle position sensor...I'm bringing it to my mechanic Monday and thats the first thing ill ask him to check...thanks for the help tho