PO303...help

mopar9012 · #1 08-21-2011, 07:32 AM

Well it all started when I cranked up the truck on morning and it was sputtering really bad. I replaced the plug wires and plugs with BOSCH plugs and that made the truck idle good and not sputter but then it would buck at LOW rpms going up a hill. So I read that I should have only used motorcraft or autolite plugs in my truck. So I bought some motorcraft ones and gapped them to .44. Now I have a misfire on piston 3. The boot still have the metal piece still in there and nothing is wrong with the plug.

Im really scratching my head, the only thing I could think of would be that I had a pretty bad antifreeze leak that would drip all over that piston/plug area. I just replaced the hoses yesterday but maybe some antifreeze got up in there? I wiped off the end of the plug. Nothing helps. I checked to make sure I have the firing order correct, I do. This is really pissing me off.

ranger0130 · #2 08-21-2011, 09:23 AM

under the hood there should be a sticker saying what the spark plug gap should be. Maybe your gap is whats causing it? If not pull wire 3 off the coil pack and see if it sparks.

mopar9012 · #3 08-21-2011, 10:30 AM

well the manual says .042 to .046. I should be right at .044 on the gaps but I will double check that one.

all I need to do is un plug it from the coil pack and try to crank the truck and it should spark?

ranger0130 · #4 08-21-2011, 10:57 AM

have it un plugged from the coil and start the engine, use a pair of rubber gripped pliers and hold the wire about an inch from the coil (right where you unplugged it from) and if it sparks you know the coil isnt the problem.

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The gap should be right then if thats what the manual says.