This has got me worried

[MGRISHAM]

My 98 coupe (not LSC) has developed this problem. First off the transmission shifts correctly under normal throttle, but from a roll (20 mph or so) WOT the rpm will jump up to 4000 and the car will not accelerate, almost acting like it is in neutral. Back off the throttle and everything returns to normal. On an other note I have had a miss for some time that comes and goes, so I have replaced all 8 plugs, 8 boots, 8 coils, cleaned maf, new TPS, New fuel pressure regulator. I am having the valve cover gaskets replaced now because they were leaking and some traces were found on the old plug boots, I hope this takes care of the on and off miss. I just want to get my 98 to run like my 94 which runs like new with all the fun a Mark VIII can deliver. Anybody have any ideas about my WOT problem. Thanks Mark