If it's only running like crap when it's hot, your 2ndaries may be stuck open. This doesn't always trigger a CEL, but if that's the problem, the code is in there somewhere....

Does it still run like crap at highway speeds/upper RPMs (> 4000)? Or just the low end? If so, that very well may be your problem. Nothing's really "wrong" with the 2ndaries, it's just that the control box (IMRC) is just *baking* there on top of the intake manifold. This has been known to lead to intermittent problems with the 2ndaries. It's happened to some of the San Diego guys, and (I just learned, thanks to Alex Peper) me too.

-Chuck Dienzo Black 98.5 E1 SVT #5022 of 6535 Born on March 16, 1998 "If trees could scream, would we be so cavalier about cutting them down? We might, if they screamed all the time, for no good reason."