P0157 Only on hard acceleration

[TheEnder53]

Hello everyone.

I’m going through repairing everything on my 01 Tahoe.

Right now, on hard acceleration at wide open throttle it sets a P0157. If i don’t drive it hard everything is ok and the code will never set.

02 sensor voltage according to HP tuners for B2S2 is quite low from what i remember seeing with engine off cold. Looking for a direction to go in with this. 02 sensor was replaced with one from Autozone. Didn’t fix it.

 

[Fless]

Any exhaust leaks before or right after the cat? Something to cause it to run lean when you're at WOT?

What do the short- and long-term fuel trims look like?

 

[TheEnder53]

Any exhaust leaks before or right after the cat? Something to cause it to run lean when you're at WOT?

What do the short- and long-term fuel trims look like?

From what I can tell, absolutely no exhaust leaks from the exhaust manifold back to the B2S2 02 sensor. Even has all its exhaust manifold bolts still.

If I recall correctly, using HP tuners, short term fuel trims would jump all the way into the positive red (and i think long term would too, i need to look again) until I let off the gas.

 

[TheEnder53]

Apologies for delays too, been very busy with family stuff.