Changed plugs yesterday. Cleaned out coils but I did NOT put grease around the edge of it. I'm getting a random misfire. Started the truck and unplugged the coils one by one - they all caused it to stumble...so obviously they are all getting spark to a certain extent.

Replaced the fuel filter about 6-7K ago.

Best place to go from here?

 

do you have sprak plug wires, im assumin since your truck in a 2000?

 

if he has the 5.4 then he'd have cop ignition. and i'm assuming he has a 5.4 because of his username. can you feel a misfire?

 

ok, well in that case, he can try to reset the pcm. Also perform an injector flush

 

Whenever it happens the RPM's slightly drop, and it bucks/stumbles.

 

Low grade misfire = Happens under a load, usually @ 45-50 mph right after the shift into OD under normal acceleration. Rebooting will only slightly offset the miss for a short period of time.

There's a few options.

1. Stress Test via WDS.

2. Accelerate normally until miss is at max, then hit the gas,- HARD in effort to produce DTC,- directing you to problem cylinder.

3. Replace them all since a set of new ones are cheaper than the old units are just to get tested.

Injector's VERY RARLY get bad enough to cause this problem.

 

been having trouble with mine for a while and now i have found that it is an injector. I also pulled every plug and it caused the engine to sumble on everyone but the back passenger. then i pulled the plug and put it in the boot and cranked it and it sparked. so i knew it wasnt the plug. then i pulled the injector electronic plug on all and it made it stumble on all but that one. so i assume it is the injector. im running a thing of injector cleaner right now and it is running a little smoother. i hope it completely cleans it so i can have my truck back to normal.

 

Since his problem occurred after an ignition update, it almost has to be related.

A couple things can go wrong with an update.-

1. The boot can be off center and can,-has folded instead of mounting the plug correctly, BUT that leads to primary failure and a DTC. So, not the case here.

2. The spring could be pulled from the coil blade enough to cause this problem, but then again, -I doubt it in this case.

Since ignition integrity seems to play a roll with these COP systems, the coils may have went back on different cylinders. This doesn't always fly and results in this problem. It's my guess that is what happened here, UNLESS the OP used Autolite or Bosch plugs = Totally bad move, this causes Ignition havoc. One more possibility, -the harness could have been routed incorrectly over by the BIG plug connections. If resting on the AC accumulator, the Mag Field can disrupt the ignition system to a point of intermittent misfire.

 

Right! also a power balance should tell you in the IDS. Rarely but injectors do go bad. Also what kind of plugs?

 

Why not? That's essential with COP.

 

Motorcraft plugs.

GLC:

Didn't even think about it. Might pull all the coils and put grease around the rim.

 

Coil windings (spelling? dooeee) break down and shear over time. When to many are gone they begin to cause load misfires. Changing up the ignition in any way could have caused a few to many to "shear". When this starts happening it's like domino's lol, I don't even screw with any more. It's best to change them all out and be done with it. $76 buys you a whole set of OEM's guaranteed for life.

 

Im pretty sure there's an update refalsh for your pcm too

 

My 2002 5.4 is doing this as well. Had all the plugs/coil packs replaced w/ OEM MOTORCRAFT plugs-coils.My Cousin at a dealership did the work back in July of this year.The mass-air sensor is clean as well as the throttle body.Tried a couple of cans of sea-foam injector cleaner. It helped a little but not much. Tried a couple of tanks of premium gas-93 octane as well. No luck still does it.Im stumped I really don't know where to turn next except of the IAC solinoid or the PCV valve. Also my gas pedal seems to be sticking when it is cold in the morning and after the truck sits at work all day. Could these two things be related?

 

You have a problem in the throttle body, either it's not clean or the throttle plate is misaligned.