So as most of you know, my car has been throwing a P0171 code meaning system bank lean saying its caused by the secondairy air injection.

Well today, the car started surging hard upon accellertation as if it had power and then didnt and then did. It was also backfireing like mad. I pulled codes and it now says P0170 instead of 10171 which is system back lean AND fuel trim.

so this is killing me, ive been dealing with this for over a year and no place ahs been able to fix it. PLEASE HELP




btw, sorry for mis-typing or whateva. im hammerd and im on ambienl w00t

 

Check for vacuum leaks.

 

Sounds just like my problem. Mine acts up worse when the temperature is under 40 degree.
This is the thread I started and it lists the stuff I have done already.
https://www.audiforums.com/m_832471/tm.htm

What have you replaced so far?

 

there are no vacuumed or boost leaks, i have replaced the MAF, cleaned the O2 sensor...

Im going to bring it into Audi to find out whether it is a sensor for my secondary air injection or the actual pump

 

My uncle just pointed me toward this vac pump that is on a recall. It has a tendency to split in the cold causing many different problems. $25 for part #058133753B

 

I can almost guarantee you need a new MAF. The P0171 signal is what i got, and it went away after replacing my MAF

 

If you're backfiring, check the timing on your spark plugs. What are they gapped to? Swap them out for what they come preset from the factory, and see if that mends the whole KABLAMO thing going on. Also, you running rich will probably correspond somewhat to your MAF. Hopefully that helps some, good luck solving your problamz

 

He did already. The next thing the 171 code points to is the coolant temp. sensor. I had the same symptoms and codes and have spent about $400 chasing this problem. I will post if this $25 suction pump fixes the problem. (for me at least)

 

Changed the pump last night and the car seems to be fine on the drive to work this morning. No bucking and no surging.

 

I am running lean, not rich according to the computer. The spark plugs i am not sure of. I will check them but i do not believe they are the problem. Also, no one seems to know what the secondary air injection is. The computer tells me that is the problem. anyone??