Chevrolet Repair: 1998 chevy 4x4 1500 5.7 liter, actron scanner, chevy 4x4

Question
My truck is a 1998 chevy 4x4 1500 5.7 liter. one month after i baught this truck, i had water in the oil. so i checked the intake gaskets and they were bad. i crossed my fingers and replaced them with no troubles. no more problems there. i have had the truck for 4 1/2 months now and  my problem is i'm guessing something in the fuel system. for one thing my fuel pump seems to be really loud after being started, it sort of whines loud. for 2 sometimes while driving it seems to miss, loose power, and be doggish. i have a actron scanner and everything read fine with no codes found. i checked fuel pressure and it reads what service manual says. i'm pretty sure i have checked everything, incliuding every sensor i can find.the only thing i have not done yet is drop the gas tank and inspect the fuel pump. the scanner read me the emissions but my service book does not tell me what mine are supose to be, so i can't tell if they are good or bad. i'm going crazy not knowing what to look at next. can you lead to the right place, can you tell me the emissions on this truck or tell me what to check next? . i'm trying not to spend the money at a shop or dealer. i'm auto savy but this ones got me stumped. thank you  

Answer
ok. im going to have to say stick with the fuel pump. if its louder than it normally is, then something is going on there. also, if something is wrong that its whining, the resistance is much higher than it should be, and its drawing more amps than its supposed to which means the unit is heating up, and that could cause a flow problem. is the vehicle a hard start when its warmed up? i would say for now pursue the fuel pump problem, but dont rule out air or spark.