help! 02 gmc gas savana

[59 camaro]

i have this 02 gmc savana cargo bob tail i just picked up 1 month ago. ive changed fuel, air oil filters n flushed tranny oil.
problem its been having it takes toooooo long to turn on n im thinking the fuel pump might be the problem. what do you guys think? i just want to avoid the problem b4 it leaves me stranded on the road. thanks for all the help

btw its a gmc 3500 w 5.7 gas

 

[lotsofmiles]

My 99 has been VERY picky since summer gas. Fill up at one station and within 10 minutes its running like crap. Ive narrowed it down to a couple gas stations and stay away from them.
Friend of mine with a 2000 is having the same issues.