Hello all,
I'm not new to the forum but this is my first post. I have a 2006 base model with 45,000 miles and love it! I have gotten a lot of really good advice from some really knowledgable people on here. I recently did the Magnaflow exhaust, K&N intake, and pcm tune all myself. The problem is that when I shut the Hummer off I'm getting a little bit of a backfire. Can anyone give me some advice or possible reasons for this? Thanks!

 

Hello and Welcome from MI. I have not heard of this type of issue before. If you still have the stock PCM I would suggest swapping it with the "tuned" PCM and see if you still have the same issue.

What PCM tune did you go with???