ant8624

ok a neighbor come to me with a problem lol....he decided to pressure wash his motor and now the check engine light is on and the codes come back that cylinders 1, 6, and 8 are misfiring.... its a 2001 ford f 150 supercrew with a 5.4 he also has a cold air intake i dont know if that could have anything to do with something getting wet or not but... i have no clue what to do or were to start... please help....ant

Poobs

Pull out the spark plug booths one at a time and blow them out with compressed air and also the spark plug wells.

Let them dery very well and maybe spray some wire dryer or other product to displace water such as WD-40.

Make sure the spray is all wiped dry before you start the motor.

Let me know if that does it.

kylebgt

I would bet good money that it is the spark plugs.
But if changing them does not solve his problem than the following is a list of other possibilites.
P0300-8
*Vacuum leak, hose connection, spray carb cleaner and monitor scan tool or multimeter hooked to ox1a+e2 ground, use ecm pinout
*Ignition system,wiring to engine coils, will usually cause 1300,1305,1310,1315 cel, or swap around to test.
*Injectors, try seafoam in tank
*Fuel pressure
*MAF sensor, clean or test with multimeter 1.1-1.5v at idle used vg+e4 use ecm pinout or scan tool
*Engine coolant temp sensor,use multimeter resistance about 2k at 68 degrees F, usually cause p0115-0119,0125.
*Compression pressure, rent tester at autozone
*Valve clearance, use feeler gauge with cam lobe pointing up
*ECM
(in some or most cases the cel takes 2 trips to return after reset)
*use scan tool with freeze frame and live data to find problem/s\

zincsvtcobra

Another thing to do is to check the coils. You can simply unclip the wire from each coil, one at a time and with the engine running. If the motor bogs down, that coil could be bad. It could be the spark plugs, but I bet the coils got wet. You can use a multi-meter with it set on the CONTINUITY (the one that buzzes). Put the red wire on one of the coil connections and the black on the other. If you hear continuity, their good. If not, their bad.