2006 Chevy Cobalt p0304 misfire cynlinder 4

Ok so I have changed spark plugs, ignition control
module , coil pack, battery, compression test , valve
cover gasket, my TCM transmission control
module stopped working so I grounded it to the car
before all this happened. I drove it for a few days
then got this code so I don't think it relates but just
throwing it out there to give as much info as
possible to figure out this cynlinder misfire code. It
seems cobalts have this problem alot and I literally
changed out everything I seen people suggest.
Even the compression test was fine. No other new
codes are coming up either so it's impossible
something else could be causing this if it was
going bad as well. I'm at a loss and have no idea
what it could be at this point. My exhaust is broke
so I can hear it sound more muffled and growls
harder than normal even when idling. It's blowing
out smoke white and the plugs have burnt carbon
on the ends after I try to run it. It also has the
check engine light flashing only when I give it gas
but when I'm not giving it gas , the check engine
light doesn't flash but stays on when I try to drive it
, it loses power and takes longer to get up in gears
and it even shifts a little harder than normal. This is
all the info i can give about the problem. Can
someone please help me, thank you I also have a
video of how it sounds when running idle maybe
that can help to idk.