[konafocuswrc]

after sct chip taken out, driven for a week..
was running perfect until yesterday..
then engine code shoed up finally, it shows P1506..

P1506 - Idle Air Control (IAC) Overspeed Error This DTC is set when the PCM detects engine idle speed that is greater than the desired rpm. IAC circuit short to GND
Damaged IAC valve
IAC valve stuck open
Vacuum leaks
Failed EVAP system
Damaged PCM
Disconnect IAC valve and look for little or no change in engine rpm as an indication of a stuck or damaged valve.

but i still cannot find out what this causes..
this got nothing to do with misfiring right?
when misfiring happens, idle speed is rough and sticks a bit..
idles rough(misfire), then in few seconds jumps upto 1000rpm and slowly goes back down to 750~800..

[Focus man. Focus.]

Have you checked or cleaned the IAC (Idle Air Control)valve?

Sorry if you have already, I really haven't been following you progress so far with your problems.

[Feral]

Remove the IAC and look for any foreign material stuck in the ports.. if not see if the plunger is stuck if it is clean it..

if that doesn't help you will most likely need a new IAC...

your symptoms are exactly the same as AckermaNzx3 Problem when we fixed it.. his turned out to be a small piece of plastic was wedged in there after he ported his intake.. he had his car chipped so it refused to throw a code my reader would error on connection and it hit me to ask about the chip he then said yeah pulled it and by next morning it threw the same code

http://www.focuscanada.net/forum/index.php...topic=25501&hl=

[konafocuswrc]

no i haven't done anything to it..

[Feral]

konafocuswrc,Nov 8 2009, 10:24 PM Wrote:no i haven't done anything to it..
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LOL not saying that you DID anything to it.. its common for the IAC's to pickup crap via the intake/manifold... its also common that raw varsal'd fuel/carbon builds up and causes the plunger to stick when it tries to control the idle

I referred to his thread because his threw the same code and was caused by the IAC's plunger stuck open to much

basically the compuuter is saying HEY IM RUNNING TO FAST, Close the IAC, IAC won't move and lower the RPM's so the computer throws a code saying I can't help you the IAC got problems

[konafocuswrc]

^^^^^ i was replying to "focus man focus"

and haven't seen your replies until now..

[konafocuswrc]

only difference from him to mine is idling..
his idling is 2000 rpm and mine is close to normal 800rpm..

how do i get to iac??is it easier to go under the car??

[Focus man. Focus.]

It should be on or near the Throtle Body. It regulates the air that bypasses the throtle plate at idle (when the plate is fully closed).

[Flofocus]

Zetec, its behind the intake manifold. PITA to get to.