P0131&P0151 codes on 97 Tahoe

I hope some one has run into this problem before,first off engine is running lean,it idles fine but when accelerated it dies and pops back into the intake.
I have checked the fuel pressure (66psi) and pressure doesn't drop after engine is cut off.All sensors monitored on my scanner(map,maf,o2,ect) seem to be reading correctly
I have sprayed carb cleaner all around intake and top of engine looking for a vaccum leak (none present )
I have checked vcm ground,o2 sensor connectorsand grounds, also did a restriction test on exhaust.
Engine has 128,000 miles and isn't skipping and injector balance is ok

Any help with the problem would be great, thanks Eddie

Sounds like the fuel pump is not supplying fuel volume. The pressure may be good but that is only half of what it needs. I would check the filter first if it is ok the suspect a bad pump. Also take a look at the cam retard pid to see where it is.

Filter is clean with no blockage,cam retard is -6 idling and reved up,also when the engine is cold and in a open loop it runs fine like there is no problem,so that should mean fuel pump has enough volume.By just taking fuel pressure gauge off from fuel check hose and cutting key on there seems to be enough volume coming out of hose.

What is the O2 voltage when it starts to run bad? I asssume it drops close to zero with it leaning out. What are the fuel trim numbers? Does the calulated engine load go above 80% at wot? If it does not this would indicate a dirty or bad MAF. Is dead head fuel pressure close to 75 lbs?

O2 voltage drops down into the teens,long term fuel trim is 1.6 at idle and 9.6 at wot ,short term trim is 7-8 at idle and 0 at wot.engine load is at 74% at wot.
I have tried a good maf off from another tahoe ,and problem is still present.dead head fuel pressure is 73psi

I hate to sound like I am beating a dead horse but if the exhaust is not plugged and the MAF is good then you have a fuel volume issue. The pressure can be beyond perfect but volume not there. Only other thing is that you got a hold of some E-85 fuel and this will cause a very lean condition. The open/closed loop issue could be no more than the pump will work when its cold besides how long before closed loop 2-3 minutes?

Idling 6 mins until closed loop with a cold start at ambient air temp at 50 deg.This is a vehicle i'm working on (on the side)not sure about the E-85 fuel( good thought on your part ),but it did act up on the people about 3 weeks ago and then cleared up,so i bet its not on that same tank of fuel.
She is a brain twister for sure,everything i have checked shows fine,but i'm not done with the old girl yet,i'm still digging

Well it was the fuel pump volume,checked another 97 truck fuel volume and there was a big difference,even though the problem pump looked as if it had enough volume
IT DIDN"T

Thanks for the help Asecmt.

Glad you got it going!!