I have a 1996 olds lss (8 it wants to throw a p0171 code lean on bank 1
I can erase the code and it will stay out sometimes for a minute other times for a day. Here is what i have done

New plugs, wires, mass air sensor, matched flow fuel injectors, all new vacuum lines, also the coil paks and controller
Then the lower end of the motor went bad so I got a l26 from a 2007 buick with 6000 miles on it.
And now I still have the same problem as before any ideas??
what am i overlooking or forgeting here??

thanks

Did you by any chance reuse any lower intake gaskets? A P0171 and a P0174 both go hand in hand if you have a major vacuum leak. with yours being on the left bank, I'm inclined to wonder if you have a bad intake gasket on the left side.

Just throwin ideas out.

brand new metal lower intake gasket new upper intake gasket too

also I changed to a metal intake instead of the plastic one and same problem

Remove and inspect your EGR tube. It'* the metal pipe that runs from the EGR to the underside of the throttle body. I just seen a couple of old posts that point to that pipe.

egr tube is new as is the egr valve (less then 6000 miles on them ) i am using the one off of the 07 buick I had this problem with the old egr as will

can a fuel pump cause this problem? that is old with 212000 miles on it

That would be a possibility considering the right bank(2) gets the fuel first, bank 1 gets the fuel last. Do you have access to a fuel pressure gauge?

Here is a similar condition that Boosty has. He'* what I consider "god" to the 3800'*. lol.
This link puts you on page three. About half way down they start talking about the ICM and ICM ground. Read the whole thing if need be. He covered alot of things chasing that P0171

https://www.gmforum.com/showthread.p...t=p0171&page=3

thank you

I was wondering can I take a computer from a 1999 oldsmobile lss (same motor) and put in my car without any problems? The 99 computer has newer software and is not a calf emissions car, My car was from calf