Just today i let my dad use my truck on and errand he called to tell me the engine light was on again! Yes again the third time i got code P0303 Misfire on cylinder 3. I have replaced the spark plug all 3 thimes and the last time all the wires and plugs ... Double platinum plugs and brand new wires all wires correctly hooked up. I get this code every month or so after the new plug. This past month tho every time i started up the truck it idles very rough for about 10 to 15 seconds then goes away so i replaced the plug today and the problem went away... BUT!!! when i start it cold... It still idles very rough for 15 seconds the u can hear it idle smooth again.like a switch going off or on i can pinpoint it. Do i need a new coil pack or MAF??? I do loose anti freeze but its coming from the drivers side head gasket and im thinking i might need a new set of heads or gaskets now :-( what should i do first?

 

Classic indication of a coolant leak into the #3 cylinder, either HG or intake man Gasket.

 

So my question now how do i check this out..... whats the steps to make sure that's what it is? I forgot to mention that the coolant i seen leaking were drops and it looked like it was coming from the freezeplug! I have also checked the oil and no antifreeze in it, also no oil in the coolant! what im wanting is to see if there are some tests to do to determine if i do have a bad head gasket???

 

Have the coolant system pressure tested, leaks should show under pressure.

 

a faulty injector will give you a miss fire too

 

So the first thing i should do is pressure test the coolant system? But would that show a bad head gasket?? Shouldnt my first thing be to check the coolant with the chemical test?

 

IMO you should go ahead and have the used oil analysis (UOA) performed. It'll tell you if the disappearing coolant is migrating into the oil, a clear sign of failed intake and/or head gaskets.

 

Okay I will do that is there somewhere local i can take it for that without having to wait weeks to mail it out? Also i changed out the plug and it has been running smooth right now. Thanks a million Rockledge I really wanna keep this truck i love it and i am willing to put the money into it. Its the best truck i have had but i know it will need work from time to time.