Idle problem, revs from 850 to 1500 rpm like it would if there was a vacuum leak or PVC line isn't hooked up. I figure it is the MAP, TPS or IAC because I can't find a vacuum leak. This is on a 01 Neon with a 2.0L SOHC. Do have a Haynes Manual but no way to pull any codes. So if anyone can lend a hand with troubleshooting this it would be greatly appreciated!!!

 

yeah sounds like a vaccuum leak to me. check all the vaccuum lines for little holes or anything, on mine they rubbed against something and over time wore a hole in it. any difference in the way it drives ? does it bog down or studder ?

 

No, this only happens in park or neutral!!! In drive or reverse it works as it should, idles at about 850rpm. When in park or neutral revs up to 1500rpm then drops off then revs up, this is cycling at about 2 or 3 revs per second. Put it in drive and it purrs like a kitten at around 850rpm. Did notice that sometime when you step on the brake, when in P or N, it will rev for about 3 to 5 seconds then go back to the 2 or 3 revs per second. Unplugged the MAP sensor and it seemed to level out at about 1000rpm but then at 2000rpm it was spitting and sputtering. Unplugged IAC and there was no effect. Haven't been able to unlock the TPS safety clip on the connector yet that's the job for today and take it to autozone and have them read the codes. Thanks for the help and anymore would be apprecaited!!!

 

will the key dance(as unreliable as it is) work on your car to try and get a code?
check breather tube for splits in the accordion folds.
the reving when u apply the brake is normal thats your vacum powered brake booster at work

 

The "key dance" will work on an '01.
insert your key into the ignition and cycle it on and off 5 times.

(on-off-on-off-on) and it will display p-codes where the odometer is.
let us know what it says

 

I've had every code come up in the odometer, as has come up on the scanner.

 

its hit n miss with the key dance my 00 it dont work at all, only with a code reader can I retrieve codes

 

Thanks everybody for all the input!!! The codes are P1684, P0601, P0108 and P0508. Do you clear all codes by disconnecting the negative battery cable? I think I need to do this ( clear the codes) because I have had the MAP, IAC and unpluged while running. Thanks again ffor the help!!!

 

disconnect battery neg for a couple of mins then re-run the car to see what codes are still present

 

Thanks, codes are P1684 and P0601.