Yet another P0171 tread

[E3Y]

Ok, I've been searching this code for the last past two months. It seems like there's a lot of answers out there but I still can't seem to fix this. In November I had my fuel pump, fuel filter, spark plugs and cables replaced. Two weeks ago I had my water pump, intake manifold and two radiator hoses replaced, and just 4 days ago I had all three O2 sensors replaced (because when my water pump went bad, it leaked into the intake manifold and they suspected that the coolant damaged the O2 sensors.) After all these replacement and I reset the code I'm still getting too lean on banks 1 & 2. I even checked for vacuum leaks. I'm lost as what else to try. Any ideas on what else it could be? Thanks.

[ssms5411]

Re: Yet another P0171 tread

What year vehicle is it?

[E3Y]

Re: Yet another P0171 tread

Sorry forgot to mention, it's a 2002, with 110400 miles on it. I got the cat and exhaust replaced about 2 years ago, because I couldn't go past 45mph.

[bigbrian442]

Re: Yet another P0171 tread

What other mods other than exhaust have you done?

[E3Y]

Re: Yet another P0171 tread

Cold air intake and a whisper lid that's it.

[bigbrian442]

Re: Yet another P0171 tread

Could be an exhaust leak before the O2's or a leaking EGR, Fuel trims have to go past 15% for the lean code to set. You don't have enough mods to require MAF re tuning.

[E3Y]

Re: Yet another P0171 tread

I asked the mechanic about the EGR and he said it's not. The fuel trim is running at 9%

[bigbrian442]

Re: Yet another P0171 tread

9% when, now ? If the long term fuel trims ever reach more than 15% the code sets. You need to be reading fuel trims as you drive with a scanner to see when they go over 15%. Have you clean the MAF yet?

[E3Y]

Re: Yet another P0171 tread

At idle it was at 9%. The mechanic had his tool plugged into the obd reader and it would surge. He wasn't sure if a new ECM would fix it but I just had it replaced with updated programming. I can feel the car idling a lot smoother than before so with all the work done it feels better. Before all the work was done just by holdin onto the steering wheel you can feel the roughness of the idle now it's just nothing. Are you suggesting that I should get a tool to plug into it and drive it around and see what it's reading at? The MAF was cleaned out by a chevrolet dealership about 2 months ago

[bigbrian442]

Re: Yet another P0171 tread

Yes...

[E3Y]

Re: Yet another P0171 tread

Do you know the actual name to the item? I'm sure autozone would carry this little bad boy?