I recently purchased an 06 cobalt SS and I've had the random cylinder misfire since day one and the dealer I bought it from has been doing everything in his power to get it fixed but the Chevy dealer who is fixing it just can't seem to figure out the problem I have also had a coolant leak somewhere and am not sure if it could be causing the misfire so far they've replaced the head cleaned the throttle body cleaned the fuel injection system out replaced the thermostat put in a new pcm changed the spark plugs as well as some other minor things I'm wondering if anyone has any other ideas of what it could be so I could inform the Chevy dealer and get it fixed once and for all any help greatly appreciated

 

Did they tell you which codes it is throwing exactly?

 

P300 I believe