i have a '99 f150 and i recently did a tune up and the third wire on the passanger side keeps popping off sometimes it will stay on for like an hour or so and sometimes it pops off as soon as i crank it i thought maybe the new wire was bad so i put the old one back on but that wasnt the case

 

buff- I had '99 but that was a couple of trucks ago so I don't remember it very well. Do the '99's have wires and not COP's ?. I have only ever seen it once before (a very long time ago on a brand new Mercury) and it was a bad plug. The compression was actually leaking slightly past the electrode in the plug and you could put the plug wire back on and watch it for a few seconds and it would pop off. The gas built up behind the spark plug boot and popped it of. Changed the plug and problem solved. If the plugs were only a little easier to change I'd switch with another cylinder and see if it popped that wire off. Probably safe to say if you put it on and rev it up some and it pops off, that's the problem.

 

Wouldn't by chance happen to be autozone wires would it? I had the same problem out of the last 2 sets of autozone wires. The first set the #1 wire came off and the second set the #7 wire came off.

But, I would at least do what the previous post advises to rule out a bad plug. What plugs are you using?

Good Luck!

 

i got them o'rileys i belive i got it fixed now but if not im going to try changing the plugs.

thanks for the help

 

buffstuffingtron what did you do to fix your problem it might help someone else out.

 

long needle nose and squeeze the open end of the connection inside the boot?