So for about nine months now I've had a 2008 cobalt SS/TC and when i first bought the car it had no codes and ran amazing (Made 308whp 298ft/lbs on 21lbs of Boost) Stock k04
but the well driving along one day the RPM's dropped the slightest amount and the car mode 0 Boost DREADED LIMP MODE
when the car is in limp if the battery is reset the car runs mint and makes full boost for about 40mins then the long term fuel catches up and it limps the short terms fueling is around 4-5
i thought i melted a cat conv and removed the cat (ONLY CODE on the car rn is for cat efficiency), since then a few codes have come up and been fixed but limp mode still stays here's everything I've changed ether for preventive maintenance or for the codes:

-thermostat
-cam potion sensor
-exhaust solenoid (to the left of the coils on the valve cover)
-downstream and upstream O2's
-MAF
-Car doesnt have a cat (as said)

if you need anymore info on the car please let me know cause i don't know all the info someone would need to possibly find out whats going on
i can data map the car so if photos would help please let me know
just a 19yr old with a car whos a lil lost thanks

-Geoff