I got a scanner and checked code p0300 says there was random misfiring , autozone told me to change the spark plugs... so the next day I just changed them and I still notice a wierd noise coming from the exhaust and engine... even when I get in the car , I feel like a it doesn't have full potential when accelerating...plz help.

Possible causes:

Improper spark plug
Insufficient compression
Incorrect fuel pressure
injector circuit is open or shorted
Fuel injectors
Intake air leak
The ignition signal circuit is open or shorted
Lack of fuel
Signal plate
Heated oxygen sensor 1
Incorrect PCV hose connection


Intake air leak is the most common, in my experience. Run at idle, spray (lightly) starter fluid around the intake tube and air filter box, up to throttle body. If there's an intake air leak, the engine speed will fluctuate.

Come back and let us know if that was it.