[tlgrant]

ok well i have been having a high idle problem, i cleaned my IAC realy well and did everything...still idling at 2200 rpms. i got pissed today and took the IAC hose off the intake and taped up the hole on the intake tube. i also taped up the IAC tube basicaly compltely blocking air to flow through it and the thing runs mint. litle low idle here and there but definatly better then constatly reving over 2k. so wtf is this bad for it ? what the hells the point of having an iac if it doesnt do shit

[superbeef1000]

you should buy a new one ,jerry rigging your stang is no way to go bro!

[mach03]

The IAC does fine when all is right, you could have a vacume leak if it
idles ok with it plugged off.

[TrueBlueGT01]

^^^^^ chase the gremlin, mach sounds right ^^^^

[Screemin3o2]

mach is right. The IAC is a stepper motor that allows air to bypass the throttle plate when the plate is closed. It also bumps the idle when the AC is on. Therefore if you block the air passage to the IAC and it runs great then you might be getting needed air through a vacuum leak. Check all your lines and possible sources of a leak.

[MSTGGT00]

+1 superbeef1000.

No cheap rigging the stang, that's a sin. I think. If not, it should be.

[ibanez570x]

To save starting a new thead.... Can some one give me a link to or explain how to clean / change my IAC... my car goes from 300 to 1000 rpms at times and i need to fix it... its annoying..

[mach03]

First you need to know that it's the IAC doing it.
Do you have a Diablo or other type of tuner that alows you to data log?

[MSTGGT00]

Aye. An SCT Xcal will work too. If you don't have one, you should. Never just go replace things for no reason.

Oh yeah, and ... mine goes from 1000 to 1300 at random. It doesn't irritate me. It just makes her growl a little. xD

[ibanez570x]

nope no tuner.... not yet... what else could cause the annoying idle? I did put on a catless midpipe.. Could that do it possibly?

[mach03]

Exhaust back pressure sensor might be the culprit.
w/o proper diagnostic eqpt tou could through alot of $ out the window and not fix a thing.

[ibanez570x]

whelp.... looks like im getting a tuner.... now, I have heard tons of people saying tons of things... Which tuner works better, and most importantly why?

[Boomer]

Originally Posted by mach03 Exhaust back pressure sensor might be the culprit. w/o proper diagnostic eqpt tou could through alot of $ out the window and not fix a thing.

Please, I have to know where is this sensor ? There are 4 sensors on the exhaust all 02's where is EBPS or whatever your calling it ?

[ibanez570x]

i was wondering that myself... when i changed it the only sensors i saw were 02.... moreover i put MIL eliminators on the back two...

[mach03]

Their usualy mounted to the intake and have a small tube running to and from the EGR pipe.

[Boomer]

That has nothing to do with back pressure, it measure the nox levels and adjusts the amount of exhaust gas being sent thru. Back pressure has nothing to do with it at all, only nox values...

[Screemin3o2]

I was thinking the same thing when I read that. I have never heard of a sensor that measures back pressure.

[mach03]

D=diferential
P=pressure
F=feedback
E=EGR
http://www.tomco-inc.com/Catalog/dpfe%20sensors.pdf

[mach03]

Follow up
The NOX readings are used to diagnose possible dpfe problems because when it malfunctions those readings are affected.
It works by comparing back pressure at two points in the system and its readings determin(in part)the rate and extent the egr is opened.

[Screemin3o2]

Yeah, I know what the DPFE is; I just didn't know it actually measured the pressure. I didn't know that's what you were talking about.