1990 k1500 running bad

Hey I have a 90 k1500 Chevy truck with the Ytbi 350/5.7l I'm having a problem with it. What it does is I can get in it and crank it up drive 7 miles into town go in a store stay bout 30 mins come back out get in it crank it up put in drive and it stumbles and if u take your foot off the gas it will cut off and won't crank back up I have to poor gas in tbi to start it then it's fine fuel pump is working when it acts up my buddy said the injectors are not spraying when I spin the engine over it's a great running truck never had any running problem till now I've change coolent temp sensor Cuz it was broke any advice?