So i got the code p0300 im getting a really bad misfire it dosent happen all the time, spark plugs are fairly new coils only have about 40000 miles on them, what ive done was do the idle check i started to unplug coil 1 3 5 7 one at a time and the idle didnt change the whole drivers side cylinders were misfiring i checked the passenger side 2 4 6 8 and started to unplug the coil one by one and all of them seem to be working because the idle dropped, the only thing i replaced was the crank sensor im running out of ideas please help!!! Like i said it dosent do it all the time but its been getting a little worse.

 

Gummed up fuel injector? Try some fuel injector cleaner. Can't hurt, doesn't cost much.

 

when it starts misfiring do a compression test and see witch one is down could be a burnt valve