My 03' H2 started popping up a check engine light about 2 months ago so I had it immediately checked. It read Code P0174 (System too Lean Bank 2). This is normally due to a clogged air filter, cracked air intake, or bad Oxygen Sensor. So I removed the air filter (cleaned it) and did a QUICK check of the intake. It turned off. It only lasted a week, but turned off again a day later. For the next two months it would stay on longer and longer but always shut off. Today I read the CEL and it pulls up both Codes P0174 and P0171 (System too Lean Bank 1). I had bought the Oxygen Sensors and was getting ready to install them, but while popping the hood I noticed the intake pipe was a bit loose so I removed the entire intake and I found out that someone before me had incorrectly installed and left a folded piece of the pipe on the inside of the seal which caused a good air leak. (See Pic) I never noticed it the first time because I had never removed it The CEL shut off and has not come back on since.

 

A cheap fix is always good.

 

While maybe not cheap, cold air intake systems :-)

 

I like the looks of that air doc system. I think the stock airbox flows enough and the main bottleneck is in the duct. I might have to order one.

 

I have the AirDoc on my rig, it works great with the stock air box and a Airaid filter. No intake trouble or codes ever.

 

I would recommend the Volant box, sits in the same area and still sucks air from the fender as stock. I'm surprised with as much tube that is still open it was throwing those codes. I plan on grabbing an AirDoc eventually but they are pretty expensive IMO for what you're getting. Never the less AirDoc seems to be highly regarded around these forums!

 

I have the AirDoc and love it. No intake codes or problems.
All my problems are with the exhaust.

 

I bought my Hummer used and the same thing was done to mine that rubber boot all folded up.