You *need* to check your fuel pressure when the engine is under a load. Doing it in park will not get you the results you need, no matter how high your revs are.
You also need to get that KR under control. Do the FWI. Get that engine cooler somehow (yes do the 180* and fan bypass mod). Make sure your cat isn't clogged, and your fuel injectors are cleaned. And go over the engine with a fine-tooth comb for anything loose. Oh yeah...and make sure your O2 sensor wires are routed away from the spark plug wires.
One more thing (in ancient Chinese Man'* voice)...make sure the MAF sensor is clean.
Welcome, downwardly mobile yuppies, to the dawn of the Age of Nefarious.
1993 SSEi - FrankenJinx - dead and gone.
1994 SSE (136K strong) - 180* t-stat,HD alternator, most unequipped SSE on the club, XM radio, Kenwood CD/MP3.
2006 Chevy Malibu Maxx LTZ - Custom 2.25" manifold-back exhaust w/FM-80. Probably the only Maxx with this system.