2000 Crown Vic code 304

Have codes 304 and 308 misfire and assume the cops are bad but don't want to just throw money at it unless I'm sure. Any ideas? It sure is running that way. If they are bad is there anything to watch for when replacing them or is it pretty straight forward?

Thanks for any help.

IIRC, those indicate that the misfires are on cylinders 4 and 8. Try moving those two COPs to different cylinders, clear the DTCs, and see if the misfires move to the new cylinders. If they do than those two COPs are bad. If they do not move, look into fuel injectors, compression, and spark plugs.

If it is the COPs, the replacement is pretty straight forward. Remove the 7mm bolts from the COPs, pull the COPs out, blow a little compressed air in the hole to get out any debris or moisture, apply dielectric grease to the end of the new COPs and installation is opposite of removal. Contrary to what some might say, you do not have to remove the fuel rail to remove the COPs and plugs.

If you want to, now's a good time to just go ahead and replace all of your spark plugs. It's pretty easy, but use a torque wrench and torque them down to 16 ft-lbs WITHOUT any sort of oil or anti-seize on the threads! Inspect all of your COPs at this time and if you see any with holes or cracks in the boots, it's a good time to replace those boots, too. The boots and springs can be had pretty cheap at your local auto parts store.

If you don't replace your plugs, at least look at 4 and 8 while you have the COPs out, sometimes when they misfire, they leave a carbon track down the ceramic on the plug that the spark can follow to ground under load, causing an intermittant misfire after the repair.

Thanks very much guys. Just what I wanted to hear. I'll give it a whirl this weekend and let you know.