07 GMC LBZ 140k miles bone stock- no choice I am in Cali.
P0101-MAF senser code
P0299- turbo underboost
I am getting both not sure what to look for first.
Going to check the MAF does anyone know if it is digital or analog?
I can here the turbo spin up to high revs but not much power.
Blows black smoke under high acceleration.
Cleared codes pulled air filter to check and see if it was restricted- codes returned, so it's not the filter.
Pulled the air tube from the MAF to the turbo and let the turbo suck direct air.
No black smoke and no P0299 code however I did log P101 and P102-I expected that.
Still got the high spinning turbo with low power.
Cleaned the vane postioning senser, it was not very dirty.
Any recommendations beside starting at the MAF (cheapest fix maybe?)

 

Cleared all codes and recleaned the MAF again this is the third time.
Ran good for 3 miles.
I did a couple of full power starts from zero to 70 mph and the codes p0101 and pO299 came back.
I then pulled the MAF completely out of the system and left all other air tubes and filters in place.
Truck ran better and no p0101 or p0299 codes.
I ordered the new MAF it will be here on Tue.

 

Mine is doing the same thing after i installed my lift pump today.

 

Installed the new MAF senser.
Cleared all codes.
Wormed up the truck and ran it slowly no issues.
Did a full power from start floored up to 65 mph it produce a small amount of white smoke.
The truck went into the limp mode and would not go past 65 mph.
I then got the same trouble codes P101 and P0299.
Now where do I go?
My suggestions?

 

Im in the same boat trying to figure out mine. Have you tried cleaning out your MAP sensor?

I see your from central california, where abouts? Im in Monterey, but come to turlock often.

 

See above
Installed a new MAF senser.
Bako

 

I seen you replaced the maf but have you checked the MAP sensor? They are 2 different parts.

 

Found the problem it was the lower intercooler hose from the turbo.
$99 hose and cleared the codes, no more problems.
Truck runs great at full power and gets 18 mpg on cruse control at 55 mph.
So if any one is getting a P0299 turbo under boost check your hoses before you work on the turbo.