2006 Chevrolet TrailBlazer - Codes

po171,po300,p1133 need help

Vacuum leak

Find and repair your vacuum leak and the other 2 codes should go away.

This is a very cool post. Shows just how helpful the members can be.

Describe circumstances leading up to problem. Has anything been serviced on the engine or fuel system recently?

why does the general consensus so often seem to be “lean codes = vacuum leak” . . . ?!

I can think of plenty of instances where that wasn’t the case

Just like an evap leak code isn’t always because of the fuel filler cap

diagnosis . . .

There was not much to go on with the problem description. There are other things it could be, but a vacuum leak is the highest probability.