Hello folks, Here we go:

2009 Chevy Cobalt LT 90,000 miles

Problems:
-Cylinder 1 misfire
-P0171 (bank 1 system to lean)
-Hesitating
-stumbling
-flashing check engine light

History:
Check engine light came on about a month ago. Throttle body was cleaned and it seemed to run good for about 3 weeks. SEL came back on and this time was running worse and flashing. Codes were read and had a long history of cylinder 1 misfire as well as P0171.


What I've tried:
-replaced all the plugs
-reset codes, they came back
-moved coil pack to cylinder II
-cleared codes (code came back cylinder 1 misfire)
-verified spark jump from coil
-swapped plugs again
-removed MAF sensor (looked brand new) didn't want to mess with it

Observations:
-disconnected cylinder 1 coil and there is no noticeable difference in rough idle

I am thinking maybe a fuel injector?

Any and all help or experience with similar issues is appreciated!

 

Too many variables. Have you cleaned the MAF? Is your O2 sensor still any good? I wouldn't suspect the injector too badly. Clean the MAF for sure.

 

Moms 2.4 was having similar problems. It was a fuel injector. Swap injector to cylinder 2

Also check for vacuum leaks. Mainly injector orings

 

I think you nailed it.