Any car mechanics here? I have a question

i beg to differ the dianostic tool will get a code if one is still stored in the computer. the check engine can be out but the code not cleared. either way autozone has a website with repair manuals on it and they sell them at any auto parts store. the manual are reallly helpful and decently priced.

It's possible that the arcing from the wire to the plug may be depositing metal on the wire, making it not sit right on the plug. I can best suggest to clean the plug out or replace it, and use a conductive paste to help avoid arcing again.

i had one(individual ignition coils) go bad in my expedtion. it took a while for check engine to come on. if you dont my me asking its a99 ford expedition with what size motor and is it 4WD?

thanx guys. Okay, I definitely know that I have spark plugs and not ignition coils as I purchased the parts for a tune up (plugs, wires, filter and pcv). My one sister-in-laws bf used to work for ford as a mechanic and he has the computer reader, which, when hooked up to my car, told him it was one of the plugs. Thats how we realized that the one kept getting loose. As for it leaving deposit in the cap, thats a possibility. I will also look into getting the conductive paste. In the meantime, I will pull the wire and see if I can squeeze it a bit tighter to fit better until I can get to the store. Like I mentioned earlier, it last for a day or two and then I'm sitting on my engine to push the wire onto the plug. thanx everyone for the help and suggestions. Its nice to have someplace to ask questions. :D

your welcome. sorry i couldn't be more help. i definitely try changing the wires then.:)

Generally when a spark plug wire is attached properly to the plug you can feel it snap into place and when you lightly tug on it, it stays on. If you don't feel that snap when you push it on, you probably don't have it on there right.

I have pushed it on and heard and felt it "snap" on, put perhaps as was suggested by some others it might not be snug enough. I'm going to try the squeeze method tomorrow, providing I need to leave the house to take my son to school. if not, I'm staying inside in my jammies :P

The conductive paste will definitley do the trick, but it will not be a permanant fix.