hard starting

i have a 92 gmc 1500 with the 4.3 tbi..i just bought the truck a week ago and have not put alot of gas in it till today.. after i put 20 bucks in gas in it it started being hard to start and while i am trying to start it it smokes out the tail pipe.. i was thinking maybe its the fuel pump.. just really strange that it starts after puting that much gas in it.. pls help me figure it out i am going to check the fuel pressure in a lil bit ...