gyea

Since the day i bought my stang i have put 10s of thousands of miles on it without ANY problems and go figure the other day talking about how great its been running over the time i start it up this morning and its starts misfiring and gas is coming out of the exhaust I checked all the spark plugs and cylinder 3 looked pretty black all the others looked fine but i replaced them all anyways and turned it over still has a horrible idle and gas coming out the exhaust next i bought a obdII scan tool and ran it no errors codes... not a one! what the hell is wrong here ?!?!?!?!

ChalknCover

Your wires may need to be replaced, you should have done that with the plugs. If the current isn't getting to the plug, it won't fire, so it is not igniting the fuel, which is just going to push it out into the exhaust. I would do wires first, then tell us if that fixed the problem.

gyea

replaced the coil pack wires and plugs no gas in the exhaust anymore but still a terrible idle any other suggestions?

abingdonmustangs08

Put like 2 bottles of octane boost in your tank when its close to empty, ( like 1/4 tank or less) get on a major highway and open it up as hard as you can. After 10s of thousands of miles you get a lot of carbon build up. You might have a little piece of carbon build up on a valve. So your vavle isn't closing all the way cuasing it to missfire. I've experienced this myself.