2001, F150SC, 4x4, 4.6, 94K miles,

<o></o>Engine was running rough, then CEL, I pulled the code P0308 #8 misfire.
Pulled the coil, it was wet inside, dried it out and swapped it with #1 coil.

Engine ran better for a very short time (25 miles) then back to P0308

<o></o>Changed all eight plugs, #8 had corrosion thought I had it.

Again engine ran okay for a few miles, then slight miss and the “Theft” light would randomly blink when engine would miss. After 100 miles of this the CEL came on again and back to P0308. Engine is running rough again, and I don’t notice the “Theft” light anymore.<o>
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I was hoping for the problem to follow the coil but no luck.<o> </o>

Tonight I plan to pull #8 coil and plug and look for moisture, Check the electrical connection to the coil for corrosion.<o>
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Any other ideas?
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Thanks,
John

 

P0308 Misfire Detection Monitor Detailed Description
The misfire detection monitor is designed to monitor engine misfire and identify the specific cylinder in which the misfire has occurred. Misfire is defined as lack of combustion in a cylinder due to absence of spark, poor fuel metering, poor compression, or any other cause.

Possible causes :-
Ignition System.
Fuel Injectors.
Running out of fuel.
EVAP canister purge valve.
Fuel Pressure.
Evaporative emission system.
Base engine.


Diagnostic Aids
The MIL will blink once per second when a misfire is detected severe enough to cause catalyst damage. If the MIL is on steady state, due to a misfire, this will indicate the threshold for emissions was exceeded and cause the vehicle to fail an inspection and maintenance tailpipe test.

 

I pulled the coil, no mositure. Pulled the plug it was dry. cleaned all connections, coil and injector connector, spring that goes on plug. Used some dielectric grease put it back together still has the miss.

Is there a way to check the injector? or any suggestions on what I should do next? I feel I could change a injector with a little help but after that not sure if I would want to go any further on my own.

 

Try tapping on the injector while it is idling. I have seen them stick. I recently had a Taurus that had a misfire code that didn't move with a plug wire swap, I took a screw driver and put it against the injector and it wasn't clicking. I tapped the injector with the handle end of the screwdriver and it started working again. It's been over a month now and no problems.

 

I tapped on the injector, measured the voltage at the connector with the key on and the engine running and compared it to another and both seem the same.

How hard is it to change the injectors? If its not too bad I was thinking swapping #8 injector with another easier access injector from the same side and see if the code will follow the injector swap?