I'm posting this question for a member of an RV board I go to who has a Q on the above. Here is his post as I copied it.

"I have a 99 ford f150 4x4 4.6 auto,355.Headers&KN air filter.I am about to change my plug wires for the 2nd time. The first set had 80,000 miles this set only hase 8,000 miles on them and the boots have broken down and they are arcing across the block.I was told to run a cooler plug to cool down the combustion chamber. Will this work or is there a nother problem?I tow about 4,800lbs on the east cost fron NJ toFLA. "

Several people suggest that the headers were too close....... Well, they obviously don't know the head and plug layout on these new Ford engines, so that's not it.

I don't think a 'colder' plug will do anything except just foul up faster and run like crap.

Any suggestions on where to start? I did say that he should try to see about getting another set of wires from the place he bought them.......

thanks.

 

I would put on another set of ford Wires, they seem to work the best (IMO) Just make sure that your hands are free of any grease and that the spark plug areas are not full of grease leading to premature failure. The fords also fit better (aka stock fit) as most aftermarket seem to have boots that are not up to snuff and wires that are too long for my taste. My dad ran an aftermarket set on his 92 Crown Vic (4.6) and they arced out in about 5,000 miles and fit terrible. I cannot remember the brand. He put Ford's on and they ran another 50,000 before he sold the car.
He also may want to check his sparkplugs for any cracks in the ceramic portion of the plug. That can contribute to arching through the boot and premature wear. If he just replaced wires the plugs could be bad and would need replaced. I have even cracked a brand new spark plug on accident when I slid the socket off the plug after I torqued it. (on another vehicle) Freak accident but it caused arching to occur. Remember Plugs only work because they follow the path of least resistance, If he puts too much anti-seeze on the threads it may force the plug to go through the boot for a ground. Check and inspect all possibilities as to why the arching can occur.
A colder plug only helps if you are having detonation problems or overheating. It can cool the combustion chamber a little bit. But it won't prevent arching as that occurs on the outside of the motor and the heat range of the plug affects the inside of the motor.
Just my opinion,
Brian

 

Thanks Brian, that's some good advice. I'll pass that along and see what happens.

He did mention that he replaced the plugs too and they were the Motorcraft ones.

Thanks again