99 expedition 5.4 random cylinder missfire also cylinder 4 missfire codes

[expo dude]

i went and degrease the engine after that had rough idle for half a day now i have an internment misfire at times while driving it will start to miss fire it has been a month since i have degrease the engine any ideas would be helpful less than a year ago i have done a complete tune up on it with new plugs and wire links. it had the coil over the plug system. the truck is reaching 183000 miles on it

 

[bedrck46]

A lot can happen in a years time

 

[expo dude]

i dont know i know the boots i bought have a warranty this just could be a boot issue? or could it be a coil as well

 

[bedrck46]

when you pull the boots check them very carefully and look for and signs of a burn mark or pin hole If there is a pin hole you most likely will see a dark sport that is different than the rest of the boot.

 

[metaldrgn]

Never wash/degrease the engine. General rule of thumb. Water probably got some where it wasn't supposed to and is starting to short out the contacts or something like that. If it's #4 you may want to remove the CoP and blow out where the spark plug is and the connector, both sides, with a compressor if you have one and reinstall it then try it again.

 

[FordandPolaris]

Agreed never wash these engines. If water gets past the boot, the spark grounds to the block instead of through the plug. Try to go on a long drive and see if the water will evaporate.

 

[aircargoo]

i just seen this problem monday....misfire bank 2 i think it was. 4.6 expy 2000, was raining here in jersey last few days. was pass side and splash guard was torn,broke in wheel well. anyway,they pulled coil and it was black,burned....replaced it with a USED one from engine in yard.cleared code. restarted and ran it a while....nothing. was fine. getting wet constantly isnt good but washing motor degreasing....real iffy!! i did mine few years ago but they blew it off with air hose and my wires/boots are top of the line. its IFFY....i dont like it but clean the engine was... only certain areas get dirty in most engines when u keep up with it. no need to be spraying pressurewashing/water over top of it....mine gets done whith nose raised.drivers side gets washed cause oil lines run that side....i like it dry underneith.