papa tiger

The area where the wire and connector pins meet/join or nearby plus internally at either the cop/injector or at the ECU or nearby. Damage in the wire loom will take close inspection to observe.

Big Lew

Inspecting the wiring will be my homework when I get home. I swapped fuel injectors with another cylinder and there wasn't a change. When I changed the COP last night the same cylinder showed misfire but the truck runs different now. It acts like it doesn't know how to shift right. I don't know if that is a part of the misfire or maybe something else showing its ugly head.

papa tiger

Disconnet the battery for 15 and reset the ECU, let it relearn ?

redfishtd

I would put a new injector in number 5 . No amount of cleaning is going to cure a electrical problem with an injector. I just replaced one in number 1 , 33 bucks auto zone. Mine was intermittent at 139k , plan to replace them all soon . Clean the holes in the intake with a very oily rag to keep crap out of engine. Engine oil all the o rings on injectors to install. At 60 mph around 2000rpm roughly =(2000 x 139000)/2=139 million cycles of operation , that's a lot for an electric switch .

Big Lew

Ok guys, I finally have an update. Although not much of a change. I checked compression and it is good. The #5 measured at 200 lbs and the others were all within 5 plus or minus.

So, to roll up what I've done. Motorcraft Spark Plugs (all 8), Motorcraft COP on #5, Cleaned Fuel system, Swapped Injectors, checked continuity on electrical connector for COP, I even hooked up an inline spark checker to watch it flash as the engine run. I can see no evidence of stray voltage, there are no cracks in the harness that I have noticed. I can honestly say the only thing I haven't done is hit it with a big ***** hammer for good measure or maybe a telephone pole.

With good compression and changing the obvious things back to OEM parts I cant help but think it is electrical somewhere. I know electricity can be funny, but im not laughing anymore.

redfishtd

change electrical connector on number 5 injector, change electrical connector on number 5 cop . I haven't had to do that yet myself but I would want to have a nice pigtail on new connector to eliminate some possible bad wire near the injector or cop.
Those seem easy fixes to eliminate an intermittent connection . If that doesn't work . Then I would think about a bad hydraulic lifter .

redfishtd

change electrical connector on number 5 injector, change electrical connector on number 5 cop . I haven't had to do that yet myself but I would want to have a nice pigtail on new connector to eliminate some possible bad wire near the injector or cop.
Those seem easy fixes to eliminate an intermittent connection . If that doesn't work . Then I would think about a bad hydraulic lifter .

papa tiger

It simply is time for a pro. Encourage an electrical diagnosis ( he may find more info) or look for a code then reset the ECU first, let it relearn for 50 miles, if fruitless double check the electrical connection at the Crank than do the aforementioned. If you had misses at more than one cylinder I would believe a fuel delivery problem to the motor from the tank. Have you bore scoped the cylinder to see if it is crystal clean (water getting in there) from intake gasket.

jdinner

Have you checked the wires at the ECU?
#5 COP has two wires - PK-WH goes to a common 'Ignition Transformer Capacitor' then to ground. The other wire is LG-YE and runs to pin #10 at the ECU connector C175E closest to the fender.

#5 Injector has two wires – RD is common power with all the injectors. The other is TN-BK and goes to pin #54 at the same ECU connector C175E

Try disconnecting the ECU connectors to check for corrosion on the pins. When you find the wire, try running a temporary wire in parallel to see if works.

papa tiger

Water getting into the combustion chamber will force a miss also sometimes a steam knock sound at off idle RPMS without a load on it, if you have certain knowledge most everything is good. Bore scope it if so, look for a very clean piston top (steam cleaned) compared to adjacent cyl. pistons that will be more nasty looking. A motor with many thousands of miles on it will have a dirty look in there where as steam will clean one or wet it depending on severity if so you are close to hydrolock.