Hello all. 2011 2.2L. Chugs, rpm’s up and down at idle after 10-15 minutes. Eventually dies if I don’t keep foot on gas. No codes. Have changed spark plugs and coil packs, double checked gap on non acdelco plugs(I know now), cleaned throttle body, new air filter, cleaned maf sensor twice, used fuel injector cleaner twice 2 weeks apart. Any suggestions on next steps? Thank you.

 

Put in the correct AC Delco 41-103 spark plugs and resist at all costs to attempt to gap them that little iridium whisker can break off pretty easily, rendering a useless plug. Have a look at the existing plugs, you might see one or two damaged plugs. You say no codes, but you also don’t say how many miles are on the clock, if over 100,000, consider the timing chain also . And I think a fuel pressure test will determine the fuel pump’s ability to operate within its pressure expectations.

 

Everything Oldblue said. Also consider a compression test. Also, keep checking for codes, including pending. Any smoke or smell when it's acting up? What kind of fuel? (Brand and grade, every use E85? Just curious.)

Do check for evedence of fuel line leak, dripes or smell immediately up shutdown, especially near the front of the driver side rear wheel.

Did you change coils and plugs because of chugging? What kind of coils? Did you save the old ones? Did all the old plugs look the same? When you get rid of those wrong plugs, be sure to note with a sharpy which cylinder each came from and maybe post picks here.

Any recent prior work to the car, or engine mods of any sort, including intake and exhaust.

With sputtery and stalling, I find no codes surprising.