Engine Loping at Idle
07 Cobalt LS, 2.2
At idle engine lopes/surges, occasionally stalls. Does the same when slowing down and coming to a stop at a red light/stop sign. If place it into neutral will stop and run normal. Having AC on seems to make it worse.
Replaced fuel pump 3 years ago.
Replaced throttle body/tps sensor 2 years ago with ac delco brand
Replaced MAP sensor this year
Replaced Fuel Filter this year
replaced plugs last year
At the time I replaced Throttle body was throwing a code for throttle position sensor. Code went away after replacement, but code is back now, along with an o2 sensor and running lean.
Not sure what to do now. Purge canister or MAF sensor?
Anywhere I should start looking next? or replace throttle body again? I guess it's possible I could have gotten a bad one at the time.