Q&A

 Rookie

I asked a friend who works on vehicals everyday and he said it was the EGR valve, but the model I have dose not have a EGR valve, what could be the cause, I do have a check engine light on. This only happens at Highway speed, when the trailblazer has made it's final shift, and we are cruzing. Just want to know a little before I get the run around at the shop!