P0505

Another CE light, and Auto Zone pulled the code as P0505 (Idle Control System). I just replaced the IAC again a couple of months ago when CE light came on and the idle was surging. Car ran fine afterwards but the idle was a bit high (@ 1000rpm) when I put it back together. After a few days of driving it settled down to @850.

CE light came back on with the P0505 but no idle problems so I reset and cleared it. Idle went back up to 1000 and after a few days of driving settled back down to 850-900 but the CE light came back on.

Doesn't seem to be the IAC and I can't find a vacuum leak.

What are my other options here that would cause a high idle to the point the IAC can't adjust for it? Bad BISS? MAF?

Car runs fine but the frigging red light just won't go out... it stares at me.. unblinking..

Cleaning the throttle body and MAF may work.

I would probably try another IAC too.

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Originally Posted by oakrdrs187

Cleaning the throttle body and MAF may work.

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Cleaned the throttle body a couple months back when I replaced the IAC.

What would you recommend for cleaning the MAF? Regular MAF cleaner or something like that CRC electronics cleaner? I saw a couple of posts that recommended not using MAF cleaner on the Mitsubishi MAFs.

I've had this problem before with an incorrectly adjusted biss. I would first check to make sure it isnt leaking at the biss o-ring.

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Originally Posted by M-Rod

I've had this problem before with an incorrectly adjusted biss. I would first check to make sure it isnt leaking at the biss o-ring.

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I've tried to avoid messing with the BISS. Will it unscrew all the way without coming apart? And is it a fairly standard sized oring or do I need to try and order it?

Before you do all that, check for vacuum leaks by get brake cleaner and spray around as it idles, listen for chnages.

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Originally Posted by oakrdrs187

Before you do all that, check for vacuum leaks by get brake cleaner and spray around as it idles, listen for chnages.

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I tried that with starter fluid... no change at all. Is brake cleaner a better choice for that?