You cleaned the MAF with "air cleaner" (compressed air, I assume) or MAF cleaner? Right tool for the job, and all that...

CRC 05110 Mass Air Flow Sensor Cleaner - 11 Wt Oz. : Amazon.com : Automotive

 

Correct I didn't use that. = (

Is that the difference between a clean MAF and Dirty one?

 

P0171: From the Service Manual.
Vacuum hoses-split, kinked, improper connections.
Insufficient fuel in tank.
Low fuel pressure.
Fuel contamination.
Malfunctioning furl injectors.
Missing, restricted, or leaking exhaust components.
Vacuum leaks at the intake manifold, throttle body, or injector o-rings.
Leaks in the air induction system and intake ducts or missing filter.
Cracked EVAP canister.
Evaporative pipes obstructed or leaking.
Crankcase ventilation system leak.
Also loose oil cap or dipstick.

 

Sure a looooooooooooong list.

 

Most common problem to throw a p0171 code is either a vacuum leak or a collapsed vacuum line.

 

Whats the most affordable way to test for these things, I need to smog it next month.

 

Technically, listening for a hissing sound is the easiest method of vacuum leak detection. The next step involves injecting smoke into the engine via a smoke machine. If the truck runs bad I would assume low fuel pressure or major vacuum leak.

The 'chilton' list is BS as I diag problems like this every day. Lean on a Chevy means air/vacuum leak, low fuel pressure due to fuel pump, or bad airflow sensor or connection to. Once in a blue moon I see a bad oxygen sensor. I do not know if your engine runs fine or if you hear any hissing noises from the engine...

 

The "List" I posted above is from the GM Service Manual.

 

What year/engine/mileage are we discussing? When you ask "what else besides an air leak", does that mean that you have eliminated air leaking as a possible source of the DTC? You could still have a bad MAF sensor.

 

It's a 2005 5cyl 3.5 88k miles on it. I couldn't hear any hissing at all when I was checking under the hood. The only noticeable effect is it seems to have less HP. Doesn't seem to get up as good.

 

One of the most common problems is a leak somewhere in the air induction system. You should examine the entire intake system for cracked, loose, deteriorated hoses or ducts. You won't always hear a leak. Your truck is eight years old, so some deterioration of the rubber hoses is expected.

 

Happen to know where I can get a detailed print of the entire Air Induction System Hosing/housing? And or Entire Intake System.

Can I just turn on the truck and spray some brake cleaner around the hosing to see if I hear the engine rev up?

 

I got this code regularly here recently when I found out my vacuum line was cracked and splitting at the ends, a simple superglue and electrical tape job kept the vacuum line serviceable for a while, but ultimately I had to replace it. Once I did, the P0171 code went bye bye! So yea, check that first, the hose is up under the intake manifold resonator. (the big, hollow, black piece of plastic with the VORTEC 2800/3500 on top of the engine) If you feel up under there on the back of the engine under the intake resonator and find it covered in a oily, watery residue, then yea, your vacuum hose is probably cracked and splitting, causing the leak. Pull that thing apart and repair it till you can get a replacement!

Disassembly of the air intake manifold is not difficult, so if you're not afraid to turn a socket wrench or a screwdriver you can get it apart, just remember how you got it apart and keep up with your screws! Hope this helps, good luck!

 

This was exactly the cause of my P0171 code. Thanks for the heads up! It was a simple fix!!

 

Thanks for the Info!! Will post my results this weekend.

 

Well I sprayed the entire Intake system with brake cleaner while the truck was running, couldn't locate a Leak at all..... O2 readings are good. The only thing That I can guess now is I have a bad MAF. Is there any way to get them cheaper then they 60+ Core fee of 30-40$ or brand new for 100+.

I hate to buy a part for 100 bucks that isn't the problem...

 

Amazon.com ($48.44) search PN 12579352. RockAuto.com ($57.79) search your vehicle.

 

Thank you!, Perfect!!!

 

Well So far.

I have first tried cleaning the MAF, didn't work. Replaced the MAF. Didn't Work, Sprayed brake cleaner on the entire intake system that was linked on this thread while my car was running. Nothing. Couldn't find a leak.

What else could it be??? This **** Engine light is stopping me from smogging the truck.

 

If you are referring to the tube that goes from the intake resonator to the camshaft cover, the GM part number is 15123628.

The tube that goes from the camshaft cover to the intake manifold appears to not be sold separate from the manifold.

I am too lazy to search through 8,229 posts looking for a clue to which engine you have.

This is for the 2.8:
ENGINE ASM-2.
AIR INTAKE SYSTEM

The 3.5:
ENGINE ASM-3.5L L5 PART 5 MANIFOLDS & RELATED PARTS
AIR INTAKE SYSTEM

 

I am referring to this which cannot be seen, only felt. Unless you remove the resonator:

So yea, check that first, the hose is up under the intake manifold resonator. (the big, hollow, black piece of plastic with the VORTEC 2800/3500 on top of the engine) If you feel up under there on the back of the engine under the intake resonator and find it covered in a oily, watery residue, then yea, your vacuum hose is probably cracked and splitting, causing the leak. Pull that thing apart and repair it till you can get a replacement!

I assume it is hose 18, but I wanted someone who has done the repair to confirm.

 

I would bet o2 sensor, on bank 1 of coarse (upstream one). MAF works on both banks. A visual inspection first is always best. Look for vc leaks too.

 

This thread is 3.5 years old. I hope he has fixed it by now.

 

Oh, OOPS, you think so? ok. OMG that is funny. Thanks, this is me ----->:clueless

Didn't you say you got that code too? recently? being that it started 3 yrs ago then its the 4 or 5 cyl

if that is the case it only has 1 bank but they still call it bank 1. Did you fix your hose? I got a lean code on my old Colorado I5 after I pulled the intake air hose to clean the TB. I forgot to put the vac hose back on under the intake air hose.

 

I have confirmed it is hose #18. You can see it is pretty cracked and the surrounding area is oily. Just need to get a new one now.

 

Yep, I think that is the one I forgot!