Got a 2001 5.4L 4x4. Had a misfire problem in cylinder 7 so i replaced all plugs and cleaned up the coil packs and plugs. Ran fine for a couple days then started misfiring again. Ran 2 thing of lucas injector cleaner through it and it didnt really help. Check engine light came on and i drove it to auto zone and it came up with P0303. misfire in cylinder 3. So i drove it home and took out #3 coil pack and cleaned it up again. I noticed some fluid around the boot where it connects to the coil pack. Also noticed that the boot was cracking all over. Cleaned it up and put it back in, and it didnt help. Any suggestions? Bad coil pack? Really dirty injector? Any help would be great.

 

You could move your coil to a different cylinder, if it acts up, you have found the problem.

 

I had the same problem yesterday, only difference is I have a 4.6 engine,
I pulled the plug from #3 cylinder and put a new one in, took care of the problem, hope this helps.

 

well after replacing a couple coil packs, i took out the #3 plug and it was covered in water. cleaned it out and its runnin good again. thanks all for the suggestions.

 

whoa why was it covered in water - did you blow a gasket

 

check plug 4 too then look at the heater hoses either the connector in the intake on the back side or the clamps on the hoses in the area dripping down

 

im not sure why it was wet, i did wash under the hood with a pressure washer a day after i changed all plugs, but i will check those hoses to make sure. number 4 looked all right.

 

also were any other boots dry rotted? it's always a good idea to replace them

 

naw no other boots were dry rotted, just # 3