These plugs came out of a 99 4.0 OHV. These are from the right side, haven't pulled the left yet.

The gap was .54 when I put them in but has grown to .80-.85. They have been in the truck a few years but only 25-30 thousand miles. I thought platinum plugs were suppose to last longer. I guess not

Here's the strange thing, the truck was running fine. No skips, or any type of hesitation when throttled up. Its a little rough at start up but straightens out real quick. I'll be buying plugs tomorrow.

I like the SP500, but will probably get the APP 103 double platinum. They are easier to find locally in my neck of the woods

 

Might the huge gap have been caused by incorrect plugs and the polarized nature of the waste spark system?
I've read a bunch about this but still can't understand how the spark energy gets to the block then jump to the center electrode.

Also the damage. Did you break them upon removal? Were they weakened by severe knocking?

 

These were Motorcraft SP-500 plugs. They were gapped at .54. Im sure the waste spark system had something to with it. These plugs came out of the right side. The left side plugs were still in good shape, gap and electrode wise, and No, I did not break them.

I replaced all six today with APP-103 double platinum plugs along with the wires. Ignition seems quicker and throttle up seems a bit better.