[Rene S. Nielsen]

Actually it might be the cat.

I had the same issue, had a code that said bad MAF (don't know the code, just got the info from the dealer) changed the MAF and still had the same code.

Then into the shop and being in Denmark where the shops don't know wery much about Hummers resulted in me changing the engine (at my own cost) because nobody cared to check the cats.

Regards
Rene