My 97 F150 5.4 2wd has a chronic miss in cylinder #7. I have changed the coil and plug twice and also swapped the injector from another cylinder. Here is what got me. When I pulled the plug out today I found that the electrode and tab where melted off. I replaced the plug and coil again to with no success. I ran a compression test and found all cylinders to be between 165 and 180 lbs. Where do I go from here. The truck has 164,000 miles and has been maintained as well as any truck on the road. It still looks great and I would like to get several more years out of it.

Thanks
spbuilder