DTC codes:

P0101
P0171
P0174
P2271

Well, we’ve been having this issue pop up for the better of the past year.

drivability isn’t affected aside from poor fuel mileage (its a hummer so not great to begin with)

2008 Hummer h3 alpha 134k miles. v8 5.3L

so far we’ve replaced:

1. MAF sensor
2. Coil Packs/Plugs/plug wires
3. 3 Oxygen sensors-replacing bank 1 upstream this week.( mechanic says o2 need to relearn procedure?)
4. Cats
5. PCV hose (hose from head on driver side to intake)
6. Smoked the intake/exhaust no leaks detected.
7. Coolant hose from the block to the heater core.(was cracked really bad and leaking onto the exhaust manifold)


im sure I’m missing something, lemme know any better thoughts. We’ve had our H3 in the shop 3 times and apparently still not fixed. The only other thing I can think of is possibly bad fuel system (I.e injector/pump)

TIA y’all.

 

Your engine is suffocating. You could try mouth to mouth, or check your cai.

 

have them do an injector balance test

 

what is CAI?

thanks for your input btw.

 

I’m taking it back to the shop on Wednesday for them to do the re-learn procedure for the o2 sensors, I’ll have them do this as well.

thank you.

 

cai = cold air intake

 

ahh thank you.

we don’t have one installed. It’s an alpha. Doesn’t seem anyone makes them for our h3s.

 

i forgot to mention I replaced the air filter.

is there any way to check the air box to make sure it’s not got any leaks?

 

open hood, disconnect cai at TB, clear codes and run to operating temp, monitor fuel trims & check if any codes return.

 

aye. I’ll give it a shot tomorrow. It’s raining here in San Antonio pretty good.

im certain it’s gonna throw a maf code since the sensor is attached to the hose to the air box from the tb.