I need help!
 

I have a '87 K5 350 TBI and i've been driving it for around 3 years now and haven't had any problems but recently every time i drive it it is sluggish once it heats up. I'll give it gas and the engine will cut off and on during acceleration. I have always done all the work on it but i am at a stand still with this. Any help would be greatly apprectated.

Have you checked fuel pressure or for a plugged exhaust?

ever change the fuel filter on that?