It's got alil over 300k miles and for some reason it keeps fouling the same 2 plugs even with foulers, so I wanted to pick y'alls imput on what the problem is or could be.

Also how much of a pain is it to replace the rear main seal? Would it be better to just wait until another motor is thrown in it if it's needed with the plug issue and if so does anyone have 1 laying around they're looking to sell. Thanks in advance

 

At 300K, it probably needs a rebuild. You could get a better idea of what's going on if you do a compression & leakdown test, and go from there. Or you could roll the dice and try just replacing the valve stem seals(I'm sure they're toast at that mileage), and hope the oil consumption lessens enough to stop fouling the plugs so quickly.

Rear mail seal is a one-piece design, so you pull the transmission to replace it. Not bad on a 2wd, little extra work on a 4x4.