I am wondering if there has been many problems with the 2002 Trailblazers, I was wondering what kind of modifications there were for this vehical.

No problems with mine now. I had a few small fixes which should be taken cared of by now. Truck run very smooth.

I've added a KN high flow air filter and a Airaid Throttle spacer. Really kicks. I'm planning to change out the intake system soon.