Ive only noticed this problem in the last couple of weeks. At first I thought it was my crappy MAC reg, but I replaced it with an Aeromotive one and I still have the problem. when the car starts up in the morning my base fuel pressure is aroung 44-45psi. when the car gets to operating temp it falls back to 40 psi. which is where i set the base pressure. I drive 20miles to work and check pressure and it fine, but if I take the car out for a beating on some back roads after a few blasts through the gears the car starts to feel slugish up top. when i pulled over to check my fuel pressurthe base psi was down to 34-35psi. So I take it easy on the car on the way home and check pressure again and its back to 40psi. This has been happening for the last few days as i have been doing this routine repeatedly to make sure it is the same problem evrytime. I have a 190 pump in, but it is used. Im wondering if the pump is heating up and not working right or is just about to crap out. Either way the car is fine driving it normally, but after a few high rpm runs it starts to lay down on the top end.