i have a miss . it started out with a check engin light i got a cylender 7 missfire i changed all plugs. it is not that bad now but still their. it will shutter at 30-55 mph. my buddy hooked it up to this computer thing and it will not pick it up . this is a 5k machaine he is using and it still wont pick up the miss. any help will be awesome. its a 2000 f-150 4.6 v8 thanks

 

Does your engine have coil on plug? If so, go buy a new coil pack and place on each cylinder until you find the bad one. I just did this with my 2001 5.4 last year due to the symptons you describe. Has been running fine ever since.....Keep in mind that sometimes the machine won't pick up the miss. I believe on our trucks, it takes about 2 minutes?? of a CONTINUOUS miss for the computer to detect it....

Echlin part # IC369 about $53 from Napa

 

yes it has a coil but i dont know witch one needs replaced because the miss will not set of the check engin light to see witch cylnder it is. but it is such a small miss that it probably wont set off the check light and is so small the computer will not pick it up right. is their anyway to tell or check coils to see if they are bad??????

 

I'm not sure of any way to tell which coil is bad. Just do yourself a favor, go to your favorite parts store, buy a coil, and start by installing it in #1 cylinder and go from there. I got lucky and found my bad coil on cylinder #2. These are very easy to swap.

 

Have your buddy with the scan tool go in to the PID in generic or OEM. The computer is very sensitive on misfires and rarely misses one, they just set the check engine light parameters so large it would have to miss for a couple minutes to set a code. In the newer Fords they are not turning the light on in the case of a misfire and are tunrning the injector off to that cylinder, logging a code, and trying to see if it will fire every few minutes. The vehicle won't fail emisons if the fuel is turned off in a misfire so they aren't required to turn the light on, so some people won't know to bring it in for warrenty, or as Ford said, They won't be annoyed by the light. There is a PID for each cylinder up to ten even though you have an eight, Ford uses the same computer program for most V8 just different calibrations. There are also PID for other sensors. Kind of neat to mess with, very helpful tool when you learn what your looking at. Took an advance OBD2 class to learn it

 

i think its gotta be a cop nothing else is showing any signs. so im going to replace the cop. one question thow? what is the difference between the oem95.00 cop and the 13.95 one they sell on e-bay.

 

o and one more thing do i need to install the same part# cop because the cheap ones are different part # but say thety will fit on the truck thanks again guys.

 

ok this does not make any sense!! i had the truck at idle i unpluged each cop one at a time. everyone of them when unpluged made the truck shutter. well after doing this to all eight. the engin sounded smooth? i turned on the ac on max for a load and it was normal a little jump and then back to normal? what gives do you think unpluging the cop and then pluging them back in fixed it? i dont know so i went for a 10 mile ride and truck ran good . any thoughts? o and by the way i had that vacume thing done to the truck yesterday and it seems to have cleaned up allot of stuff in the engin. when i got on the gas yesterday after having it done i blew out allot of what looked like carbon out the tail pipes maby this helped to dont know, but i recomend this vacume thing .

 

any comments/?????

 

You probably had a bad connection on one of the coils.
I don't think I'd take a chance with my PCM by pulling coils while it was running, though.
My $0.02

 

it didnt seem to hurt it, it just sputtered when i disconected them . i read on a forum her that is how to check them ? am i getting false info from this site?????

 

What he meant you should do is buy a replacement COP, and put it on cylinder #1. Start truck, see how it runs. If it didn't fix the problem, shut down the truck, move new COP to Cyl #2. Etc, etc.

 

but the truck is running fine now . all im saying is maby i fixed it by un conecteing and reconecting the cop's. or maby the moto vac thing fixed it . i dont no im no mechanic