I had a P0305 code ... I replaced the COP and the CEL reset on its on, engine ran fine for a few days, then the misfiring returned but no CEL after a couple days trying to figure it out the CEL finally came on. I figured the COP was bad so I switched cylinders to check it ... still got a P0305 code.

I have replace the COP and the plug ... havent got into the injectors yet. put in a bottle of injector cleaner but hasnt seemed to work yet.

so any help on where to look next would be great, thanks

 

After you swap the injector with another cylinder let us know what happened.

 

ok this is what I did ... hope you can follow

I rest the computer ( learned how to on here ) drove to autozone to see what codse I would get after reset. at autozone I got a new P0308 code (cylinder 8) the 305 code wasnt showing. well I hadn't done anything with cylinder 8 so I began to think I had another bad COP. the Guy at autozone suggested I try to clean the corroison off of the COP and try the old one (from cylinder 5). well I cleaned it up using baking soda and water. after drying it out I put a new wire set on it. and begin switching it out with number 8.

I had to remove the fuel rail ( learned to how to on here ) to get to number 8 (I was worried about that). It was as bad as I thought it would be, a little tight getting back there but when I pull the number 8 COP there was a little moisture around the top of the boot. I dried the plug well of any other moisture. put the cleaned "bad" COP back into number 8. put everything back together. reset the computer once more. drove to autozone again with no misfire. when it was checked no codes at all came back. and as of right now she is running as good as ever.

I will take the COP I got from number 8 and clean it up and have it ready for the next time.

thanks to everyone thats tried to help others on here. after reading a lot of posts it has helped me a lot

 

hey how you doin, my ford just started the rough idle and throwing the cyl. 5 misfore code, p0305 and p0316 codes. if i am understanding your postings correctly replacing the cop on cyl. 5 did not work correct? it seemed like when cleaning the cop at cyl. 8 there was moisture in the area which i could understand the rough idle and misfire, but why would we be getting a po305 code for misfire at cyl. 5? im looking to get into this this weekend, but i am reading alot of different answers to this problem. help me out man.

 

If you are getting a P0305 that you have had a misfire on #5 cylinder. The p0316 is to tell you that within the first 1000 revolutions of the crank you had a misfire.

JMC

 

My miss is giving the 0316 code several times during a drive, occuring NOT at the begining of the drive cycle so I really dont understand the first 1000 revolution thing.

Les

 

The test for misfire on startup is done in the first 1000 revolutions after the engine is started. The wording for the code is misleading because the test is not performed while the engine is cranking but only after it is running.

JMC

 

What is the resolution to this problem is what i am asking, ive seen everyon talk about it but noone ever has had an answer to it

 

Start by pulling the plug at #5 to see what it looks like. Check the COP like was done to see if there is any corrosion and what not.

JMC

 

what is the proper way of testing these cop's to ensure that it is not to be at fault?

 

Without a load tester (which the dealership uses) the only real way YOU can test one is swap it with a known good one.

 

thanks glc, so pretty much one way of testing them is to switch cop from one cyl. to another and see if it throws a misfire code at that cyl.?

 

let me rephrase that, take the cop from cyl.5 which im gettin a misfire code, and put that cop at another cyl. and see if it throws a code for a misfire at that cyl.?

 

i'm having the same problems but on cyl 1 i removed the cop and also found moisture at the top of the boot and the plug was very worn so i replaced the plug and had the cop tested at autozone and the cop was good. I put it all back together and its still missing. Autozone said the P0316 code could be a crank sensor on the shaft not reading correctly and making the cops missfire. anyone ever heard that?

 

The cranking sensor is on the bottom of the block between the ac motor and the block and looks very hard to get out. Good thing is its only $21.00 bucks to replace if thats the problem.

P.S. My trucks a 02 5.4L F150 SC with 97,000 miles