a little melting only on #1 spark plug

well I took my jeep in to a garage because of what was happening before (noisy lifters and low oil pressure) and it turns out that I have a bad sending unit so I wasn't getting the correct oil pressure at the gauge (I'm getting around 52 PSI instead of 22). Also as far as the noise goes I ran a bottle of GM EOS on my last oil change and that appears to have quieted things down. However I decided to change my plugs and, found a pretty good explanation why my motor had been missing a little. My #5 spark plug had the gap on it bridged with carbon and #6 was pretty dirty too, last time I changed them both #5 and #6 were bridged, but since then I have had it Motorvaced. To get to the point though, the thing I found most unusual is that my #1 spark plug was a little melted, the porcelin was burned in one or two places and little bits of it were all over the plug. Plug 2, 3 and 4 looked fine (kind of brownish) so I am not sure what happend with Plug #1.

If I remember correctly, the carbon buildup and cracking can indicate that the spark is too hot for your application.

I would run some good fuel/injector cleaner.
Without pictures I would say #1 is lean and #5,#6 are running rich.

When you say 1 through 6 is that front-1 and 6 is the back by the fire wall cylinder. I have this problem in my fiance's XJ, the back two cylinders usually are bridged pretty bad and the rest are just brown and pretty much clean.

yeah thats exactly what I have with mine

Edit: I should have added I am running stock Champions which I replaced with another set. RD9Y or somthing like that I think is the model # on them, they are the ones recommended in the book and arn't that expensive. I was almost thinking of using a hotter plug, since #5 and #6 have carboned up before, but now I have #1 cylinder melting a little. I am going to check these new plugs early and see what they look like before my next tune up. The plugs I replaced had about MAYBE 2500 kms on them, maybe as much as 3000.

Check inside your distributor cap too, the contacts that serve those shorted spark plugs are probably damaged now. The rotor probably eroded faster as well.
If the plug shorts, the spark current hammers the distributor contacts instead.

I've had this same thing happen, except I had shorted number 1 while changing plugs. Slowly after a second set of plugs, a cold miss gradually grew worse. It was the cap, the number one contact was bubbled and fried to crisp. Now she runs perfect.

I'll have to check that out, I replaced the cap and rotor with my last tune up but I havn't pulled the cap since.