Service engine soon p0171 Help

[kbasham03]

I have a 98 grand prix gtp with 90k miles on it. The ses light came on a couple days ago, I pulled the code with my scanner its p0171 system too lean Bank 1. So, I figured the o2 sensor took a shit so I changed the bank one 02 sensor (upstream.) The light still stayed on, I cleared it again and came back up, So then I changed the pcv valve. The light turned off for a whole day and then popped back up again the next day. I hooked the scanner up and still the same code. So I bought some carb cleaner and started spraying down vacuum lines and couldnt find any leaks. Now the ses light is on most of the time but sometimes turns off, like today for example, it was off the whole day from 5:30am to 6:30 pm but at around 7pm it came on and stayed on. I bought some maf cleaner but I dont have the torx tamper socket to remove it. The car runs perfectly fine, gas mileage is good and it still pulls hard. So I dont know if maybe the maf is going bad, or maybe the pcm is jacked, I dont know Im sick of replacing parts and not getting anywhere, anybody have a clue what the problem could be? Any educated suggestions would be greatly appreciated, Thanks. Oh, and If anyone is local to the west chicago suburbs and would be willing to swing by and take a look I will compensate you with beer and money. Thanks again.

[BNaylor]

Are you running a CAI/FWI or K&N air filter or stock air box and filter?

The MAF sensor is one of the first items that should be checked or ruled out with a P0171 lean trim DTC. So try to get the right Torx safety allen to remove and clean the wire element of the MAF with MAF spray cleaner.

If that doesn't work then then reset the PCM to clear any DTCs and disconnect the MAF. Run it without the MAF connected and see if the P0171 returns. You may get a MAF DTC but the P0171 should disappear if the MAF is the problem. Double check all vacuum lines at the throttlle body and make sure the throttle body gasket is good and/or TB is properly torqued down (nuts not loose).

[kbasham03]

Originally Posted by bnaylor

Are you running a CAI/FWI or K&N air filter or stock air box and filter?

The MAF sensor is one of the first items that should be checked or ruled out with a P0171 lean trim DTC. So try to get the right Torx safety allen to remove and clean the wire element of the MAF with MAF spray cleaner.

If that doesn't work then then reset the PCM to clear any DTCs and disconnect the MAF. Run it without the MAF connected and see if the P0171 returns. You may get a MAF DTC but the P0171 should disappear if the MAF is the problem. Double check all vacuum lines at the throttlle body and make sure the throttle body gasket is good and/or TB is properly torqued down (nuts not loose).

Im running stock intake with a k&n drop in, none of the auto parts stores seem to carry that torx driver..?

[BNaylor]

K&N drop in? Sounds like some of the filter oil may have got onto the MAF wire element which is a common problem. I got my tool at Sears. Also, Snap On Tool Co. has them.

[kbasham03]

Originally Posted by bnaylor

K&N drop in? Sounds like some of the filter oil may have got onto the MAF wire element which is a common problem. I got my tool at Sears. Also, Snap On Tool Co. has them.

Yeah sounds right, I just went into my car on my lunch break and after running about 15 min the ses turned off, so you think If I clean the connectors on the maf it will possibly be a fix..? I guess I will run to sears and see if they have it. What is it a m20 security torx driver or something like that? Thanks again.

[BNaylor]

20 rings a bell. The part that needs to be cleaned is the wire element in the plastic tube which has at least two thermal resistors. See pic below:



Good luck!

[kbasham03]

Originally Posted by bnaylor

20 rings a bell. The part that needs to be cleaned is the wire element in the plastic tube which has at least two thermal resistors. See pic below:



Good luck!

thanks for all your help ill be back if that doesnt work out.