Threw a code PO171
 

This code is lean running condition. I wasn't stepping on it when it came on. My car is at 60000 miles now, its due to get the spark plugs changed but i don't know if that would cause the problem. Should i try cleaning the MAF? (What should i use to clean it, WD-40) It never threw this code before and i've been running a custom tuned AP for a while. I read in another thread that someone had one of there recirc hoses come loose, which cause the problem. Others said that it could be caused by a boost leak, but boost is fine. Any idea's???

Thanks, Dave

And don't use WD-40 on a MAF!!! WD-40 is a lubricant, not a cleaner. Pick up some CRC MAF cleaner from just about any Kragen.

That writeup Mike posted is all good info!

that is a good post. I have a short ram intake and that never caused a problem before. I checked all connections but can't find any leaks. For now, i just used the AP to reset the ECU. If it comes back on, i know that there is a problem somewhere. The engine runs fine, no changes in performance.

We've noticed some CELs that seem to be due to altitude up here in Reno. Car gets tuned on a dyno in the Bay... runs great... comes up the mountain, and bam CEL for no apparent reason. Of course the car's I've seen this on all run great... but they do have a CEL.

On the other hand. My car seems to learn bad habits up here at altitude requiring me to reset the ECU frequently to fend of brutal hesitation that the ECU learns. But that doesn't seem to be an altitude problem... I think it's 'cause the ECU is learning to pull timing due to all the oil I get blowing into my intake from the block breathers. :(