mcmastai

Hi everyone;

I've been lurking forums for ages trying to find an answer to this problem, but I have finally decided to try and get to the bottom of it myself. I bought my '00 JDM Legacy GT-B (BH5 with the EJ206) about a month ago, and I've been chasing this issue ever since.

Basically, the car keeps throwing Code 24 (IACV malfunction) along with a check engine light. When it does this, revs sit at around 1400 and the ECU cuts fuel to cyl#1 causing the car to run on 3 cylinders. If I shut off the car, it usually "clears" the CEL and it will no longer be running in limp mode. Although the condition will return, uusually when the car is in park and the revs return to idle. However, I noticed the condition also goes away when the A/C compressor kicks in. Basically I can clear limp mode and the CEL just by cycling my A/C on and off.

I have pulled the IACV and thoroughly cleaned both it and the TB, and made sure the valve is cycling smoothly and properly. When I unplug the MAF when idling the idle gets super lumpy like the car is about to stall, making me think the MAF is good as well.

Additionally, my idle is unusually high, sitting anywhere between 1100 and 1400, and I'm getting extremely poor gas mileage (~350km to a tank). Also, on cold starts, the car will idle extremely low (1-250rpm) for a few seconds before jumping to 2000rpm, hunting for a moment, and settling in at ~1200rpm. When the idle is low, pressing the gas does not help in the slightest making me think it is running extremely lean.

In conclusion:
-car throws intermittent CEL with code 24 and limp mode. Clearable by cycling A/C.
-car has low idle on cold starts (1-200rpm)
-extremely poor gas mileage (350km to a tank)

Any help is appreciated, or if you could give me some hints of what else I could look at and try. I am planning to take the car to my tuner sometime in the next couple weeks to get the vacuum system leak tested, but other than that I am kind of at a loss.

Thanks!