gonna try that ..picking up some motorcraft plugs right now....and going to repalce the coil as well.the plug was just wet....I think they were in longer then the guy said...I think it cracked when I was trying to get my toy hauler up a hill..when it started

 

ok our compression test was strange..could not get teh hose to fully seal..lots of air came gussing out and the dial read 40....two ideas..
bad valve, or cross threaded spark plug....the spark plug caem out wet but not sure what it was that was on the threads...yes the threads...the threads were coated all the way up..no other cylinder had oil or liquid on it..what you think? and by the way thank you for your help......

 

The new plug came out wet?

If the new plug came out wet after the engine was run, I'd be inclined to get a more accurate reading if possible.. Especially after a plug/coil change and if the misfire is still present.. Does the plug look, or smell like raw fuel?

 

did not smell like gas...the new plug was not soaking like the first plug that was originally in the cylinder...I removed another plug to compare...it had no oily resedue on it at all. However the originalone had it up the threads..the compression hose would not seat on this cylinder either...we checked the coils for spark ...all of them had good spark..so my two ideas are : cross threaded ill seated plug..or bad valve or rings...gonna take it in today to have it diagognossed properly at a shop..I have runout of time to get this guy going right again..Without a scanner I am shooting in the dark and if it's a ring or valve..the scanner ain't gonna help.. thanks for your help ..I heard these were bullet proof engines..guess one toy hauler trip and it could not handle the load..

 

I'm having a similar problem. I've changed all the plugs w/ autolite double platinum as the book calls for. It cleared this problem up for about 2 weeks. Now it idles fine, runs rough up to 30 mph, and clear up to 75mph or higher. When i step on it and it downshifts, the engine cranks right up with all the power you need. Just seems like it runs 1 cylinder short through mid range. All the plugs that I took out looked like they burn well,( very light brown). I do not get a CE light but the bulb isnt blown so I know that much. Any ideas if this may be the same problem? Should I make my own thread?

 

ok update...about 2k later I have my truck back. Turns out I lost number three valve. tulliped is what they say..apparently a common issues with this truck...so it was redone and now I have my truck back......