LT1 Starts and Dies LIL HELP PLEASE

Ok it's me again with another problem I swear not one thing its another. So I drove the truck yesterday fine no problems, ( 90 C1500 with 93 LT1 ) . I get in it today to move it and it will not start. When engaging starter it starts up and then dies and acts like its about to fire then nothing. So I checked fuel pump it's good took off the fuel filter its good! Get back in it start it play with gas pedal and she started but huffed and puffed until I idles at high RPM then backed down and idled alone, it ran 20 min and then died. Started her again and same thing all over on another note when it does sit and idle and I slowly give her some gas she accelerates beautiful but if I punch it pops spits and sputters. I am thinking bad gas but wanted to post this see if anyone has any other suggestions also maybe a fouled plug??? PLMK need her back up on all legs!

Is that with the optispark ignition system?