I have a 2001 harley davidson truck with 5.4l v8 reg gas and i hook up my odb2 up to the comp. (services eng light is on) i keep getting the same code p301 witch is spark plug 1 misfire in witch i have change the spark plug and the ing coil 3 time what else can it be is there something im not doing right that the only code im getting i set the spark plug gap between 0.52 and 0.56 and bran new ing coil from auto zone and i switch it with one of the ones that not reading on the odb2 it was #5 plug can somebody help PLEASE ?

 

Check the pins in the connector for the COP, sometimes they get pushed back and don't make good contact.

 

thank i will try that i will let u know

 

could also be:
leaking fuel injector
clogged fuel injector
leaking headgasket
blocked valves
etc etc etc


how many miles? what engine?

FYI i dont trust autozone for coils, these modular engines are very picky about what gets put on them

 

13000 2wd v8 5.4 liter reg gas well i switch with a motorcraft which was was on plug #5 and reset the comp. #5 did not come up just #1 missfire

 

13,000 or 130,000?

try moving the injectors around

 

130,000 sorry miss a 0 i wish i was 13000

 

Thank alot i will let u know what happen!!!

 

and btw what brand/model spark plug is in it? was it discolored at all when you replaced it?

 

x2

 

Motorcraft the spark plug is bruning good the gap stay between 0.52 and 0.56 no change in the gap

 

which motorcraft plug??? and was it discolored...

 

I just had the same code thrown on my expedition. Can someone tell me the location of the spark plugs on the 5.4? Like from front to back on drivers side and front to back on passenger side? Ex: 1 2 3 4 drivers side and 5 6 7 8 passenger?

 

Exact opposite. 1234 on passanger side, 5678 drivers side

 

I am having the same issue lately, check engine light on and even starts blinking sometimes. Codes P301 and P302 which are misfire on 1st and 2nd cylinders. What threw me is that not long ago I replaced all the CoPs and all plugs. About 2,000 miles ago I replaced all spark plugs, CoPs, and fuel injectors but of course that doesn't mean they couldn't have gone out on me since. One easy test you can perform is to pull the CoPs off while it is running, or I just unplug the electrical wire from the CoP, and the ones that make it almost die or start suddenly running badly will generally not be the ones with issues. I tried this yesterday with engine running I unplugged the wire harness from the CoP on cylinder 1 and nothing changed, same for cylinder 2, then I did it on cylinder 3 and the change was obvious that I had unplugged it. Therefore, I assumed that since my codes were on cylinders 1 and 2 also that those CoPs must be bad and I bought 2 more from the dealer yesterday. Planning to install those first thing in the morning and hopefully I will have my truck back in action again! I also picked up a set of 8 motorcraft plugs to go ahead and replace while I'm in there and getting intimate with her anyhow.

Before trying this CoP test yesterday I was being stubborn and didn't want to think it was the CoPs again since I had replaced them all so recently (relatively speaking) and so I performed a pressure test on the radiator to see if maybe I had blown a head gasket (cause it is running like **** with those codes, like the two cylinders are not firing at all) or if I was possibly leaking water onto the wiring to the injectors or CoPs but it turned out to hold pressure like a champ.

One last thing, when I pulled the spark plug from that 1st cylinder it looked like it had rust on the end. It wasn't in such bad shape that it looked like this was causing it not to function, but I would say it looked bad enough to make me think that it's appearance was a result of it not having been functioning for a while now. (have mostly left the truck parked after these problems began due to lack of time to troubleshoot it with work and school)