EinST

The absence of drivability problems make this a tough one. If you have access to a scanner, hook it up and watch the short-term fuel trim values at various RPMs. An air leak will cause the short-term fuel trim value to be higher at lower RPMs (think constant leak vs. varying total flow). Otherwise, suspect a defective MAF sensor.

blacknblue#2

is the fuel filter inside the tank on these trucks?

Allan In NE

Hi again Bill,

How many miles are on this truck? Remember, this guy is bumpin' four years old.

Yes, both codes are screamin' lean. Be it either from lack of fuel or abundance of air.

Is your idle speed "normal"?

Allan

EinST

The fuel pump module (on top of the fuel tank) contains the fuel filter, and fuel pressure regulator which question I see coming.

blacknblue#2

The truck is high mileage at 120K. It seems to be normal idle speed. It idles right around 600rpm and smooth. Would one of the parts store have a way to check my fuel pressure or would i need to stop the a garage for that. Im sure i have no way to check it.

07yukonjkc

Did you ever figure it out? I have the same exact issue with my 07 Denali with a 6.2.