2002 F150 5.4 TRI 4x4 175k
Starts missing after the truck is warmed up... here are my observations.
1) as mentioned its after it warms up usually 15 min or so.
2) It seems to happen only when the A/C is on. I drove around 2 days without it happening at all when A/C was off.
3) When the Miss does start the A/C starts blowing hot air.
4) when it happened today i turned off the A/C, still missing. I turned the truck off and started it backup without the A/C... engine still hot, no Miss.
5) I did get a code reading, it was my Coil Pack E, which i'm guessing is #5. But that was 3 days ago not sure if this new one is different. I also checked all the connections on it.

I'm planning on removing coil packs and checking plugs.. but with the A/C symptoms, I'm not sure how these are related or if its just a really messed up coincidence... but figured I'd throw it out there before going though all this

Any insight on this would be appreciated
Kindest regards,
Mike

 

Several 104 pin PCM truck calibrations turned off the A/C when there is a coil primary circuit DTC set. So that would be software.
Primary circuit codes are uncommon but they have a typical culprit. The connector backs off the coil. So make sure the connector is fully seated and that the seal doesn't try to push it back off. I spray the connector with WD40 when the seal gets dry and starts causing problems.

 

Okay, great, well that at least makes sense. I will dive in tomorrow and update the thread with what I find. Thank you.

 

Ok, So I pulled the #5 coil It looks to be ok. They have maybe 30 to 40k on them. I'm going to swap #1 and #5 to see if the problem follows.
I do not see any indication of dried out seals on the COIL. I have provided some pics just in case I'm missing something.

 

after swapping coil pack 5 and 1, clearing the engine code, the problem returned at the same cylinder. P0355 "Ignition Coil E Primary Control Circuit/Open"

Tomorrow I will check my connections more thoroughly...
Other than that I am kind of at a loss...
Current Facts:
1) Problem is not following coil pack
2) from a cool start truck will run great for 30 min, load or no load. Then it will suddenly start to miss.
3) Seems to be only cylinder 5... at least that is what the error code is saying
4) I did notice about 30 seconds before it started to miss the idle seemed to increase maybe 100 rpm...

Right now I'm thinking connectors and maybe spark plug but not sure if the symptoms match a plug issue.

Any insight would be greatly appreciated

kindest regards,

 

One wire to the coil is "hot in run". It's the same positive circuit for all the coils. With the coil plugged in, the +12v electricity travels through the coil primary winding and back out of the other coil wire that goes to the PCM. So when the key is turned on, but before the engine is started, the PCM looks for that +12v. If it's not there you get a P035x, in this case a P0355 for cyl#5.

There are 2 scenarios where the +12v is missing and the PCM sets P0355. In one, there is just an open circuit and there is no voltage. In another, the wire between the PCM and coil is shorted to ground. In the short to ground scenario, the coil is often damaged and melted. This doesn't happen much. In the first scenario there is an open circuit and the coil is not damaged. This happens most. Aside from the connector just backing off the coil all by itself like I mentioned before, the wire can get chewed up by varmints, cut during service. Sometimes the wire can just break inside the insulation. This is probably the second most common occurrence that sets a P035x. It happens most often in the takeout between the harness and the coil connector. So in the 4" or 5" of wire in the coil connector pigtail.

Wires don't stretch. A wire that is broken inside of intact insulation does stretch. So if you have a wire that's broken inside the insulation, you can't see anything wrong with it. But if you pull on the wire, the insulation around the broken area will stretch. Pull on the wires at the coil connector pigtail one at a time and try to stretch them. You may have to strip the electrical tape first.

 

I think my 02 is having the same issue. Truck runs great without the ac on. When I start messing with the ac, after a while, the truck throws the p0355 code. It is starts stumbling a bit also. Did you ever figure out what the problem was?

 

Wanted to say thanks to you, raysorenson for the instructions here regarding the P0355 code. Been trying to troubleshoot this issue for awhile and had a more than a couple mechanics take a crack at it after changing/testing coil packs and spark plugs. They were leaning towards installing a new computer...

So, thank you. It was indeed a ground wire break in the cylinder (#5) pigtail under the electrical tape. I'm guessing it was from heat as it was a clean break. Added some insulation to it this time around.

Cheers, mate!

 

I really need help with this one. I can't make sense of it. I can't figure it out. I can drive the truck around for days with no problem, but as soon as I even turn the AC on and off, the truck will throw the p0355 soon after.

 

So we got past winter, now it's starting to warm up again, first day past 90 and my trucks AC starts blowing hot air and is missing. So as mentioned before the issue does not follow the plug or coil... I did a quick check on the wiring but probably have to do a more detailed inspection.The thing that is so strange is how its only when it gets warm out, with AC or not, just happens faster with AC on. If its cool out, I can drive all day and it will run fine... anyway.

This time I figured well, maybe the Fuel Injector... so I replaced it... first one was not did not fire... got another and it worked, however, it was a very rough idle. So i took my original, cleaned it out real good and put it back in... runs smooth so I know I didn't break anything. I'm going to test run the vehicle tomorrow (might not be hot enough to trigger @82 but maybe with AC running) Maybe I get lucky and it was a dirty injector hahaha.

So a few questions:
1) why would a new injector cause rough idle... is it because I changed only 1 and its not worn in like the others? does the computer need time to sync with it? so strange...
2) If the wiring to the injectors and coil prove to be ok... what could this be?