Check engine light came on...

[timgco]

POS HUMMER.

Have you checked your air filter, do you have an aftermarket filter? Where you in a lot of mud. There are sensors that can get plugged up.

Sice you now have the 37's, you may want to look into a Superchips or Hypertech programmer. You can adjust for tire height (not that it's off much) but you can get more driveability with the shift points and more importantly, you can check codes when things happen like this.


I wonder if you have an O2 sensor bad or clogged with dirt or something.

Try running your truck with the engine code on and hit your OnStar button and ask them for diagnostics.

Good luck.