87 gmc tbi

[IRC4FRE]

Hi, I have an 87 gmc 1/2 ton 2wd P/U. Recently I have been have some bad drivability issues. A week ago the truck has developed an erratic problem. Now this doesnt happen all the time but it is getting more frequent. I can be driving along just fine and when I give it alittle more gas it will start cutting out. And I mean cutting out. It will spit and sputter and barely run. Its like it loses all powere. It will eventually stall. It always restarts but has no power, it idles really erratic and has no accelleration. After about 3 startups it will start up and run fine, usually for about 10 minutes then, the whole thing starts again. Now this doesnt happen all the time so I am confused.
I have replaced the inline fuel filter and that didnt help. I have no idea how to check the fuel pressure so dont know if it is the pump. I am getting no SES light and it didnt jump timing. Does anyone have any ideas what this could be. This is my work truck and I need to get it working dependable again.