I have a 1998 chevy that I've been battling for a year now and it's driving me insane. When you start the truck in the morning it runs fine for maybe a minute then it starts missing, drive it down the road and it does fine. If you get in it it will bog then it will pickup and take off i checked the fuel pressure and it is 38psi key on engine off 45psi running and when you hit the throttle it jumps up to 60 psi I've changed Cap,rotor,button ,plugs, wires fuel injectors fuel pump fuel filter and the injectors are the improved version I don't know what else could cause it to have low fuel pressure, if anybody can help me I would greatly appreciate it thanks

 

when did you replace the the fuel pump? I go for that as your problem

 

I replaced it last weekend