Hey all. Did timing job on my 2012 Traverse. Everything went well. Verified there's no advance set, no vacuum leaks, phasers were tight, put new plugs and air filter in. Current Avg MPG is 11.8. Seems like garbage. Prior to timing it was 10.6. Any ideas on what to do it improve it? Could something else be wrong? O2 sensors? It still passes smog and no CEL for anything. I know it's a 12yo SUV but is that reason enough for it to be so bad?

 

How many miles on it?
Try cleaning out your throttle body. A full system diagnostic scan wouldn't hurt either. (CEL is irrelevant)