VERY strange problem, clutch maybe? Help please!

So i got my car back from having the crankshaft bolt drilled out (long story.) Since then it has been stumbling at 1/3 throttle or more after the car has been warmed up.

Now here comes the weird part. I was looking under the hood to see if anything was obviously wrong. I saw the water pump pulley moving. I noticed that ALL of the pulleys were moving! The car was parked on a slight hill, enough that it could get rolling backwards, but nothing crazy, in my driveway. I tried pusing the car backwards, it went, but with a lot of resistance. Now the only thing that makes sense to me would be an insanely shot clutch. But when I'm driving like a normal person, the car runs fine, and yet when I'm in fifth on the freeway and give it a little gas, it will stumble. I don't know where to start. By the way, no DTC or OBD-II codes. I have a 99GT with a vortech sq, accufab TB and c&l plenum.

If the engine is stumbling, it wouldnt have anything to do with the clutch. If the clutch was badly slipping, the RPMs would go up, but the car wouldnt be accelerating.

I dunno, maybe start by cleaning the MAF.

i know but maybe if the clutch is slipping it whould kinda like shudder, i don't know, i'll look into the maf, but it's a pain in the ass to rip the inlet pipe off the maf, anyone else?

I put the u/d crank pulley bolt back on after uninstalling the U/D's and forgot I was supposed to use the stock one. The bolt bottomed out and mushroomed, making it impossible to get it back out. I had a professional mechanic drill it out then helicoil the crankshaft, he said it's 100% now, I supposed he could have knocked something around like that, it was not doing this until then and has been doing it ever since.