GM-GMC: Truck Stalling problem, gmc sierra, doc moore

Question
Hello,
I have a 87 GMC Sierra with roughly 90000 miles. Anyway, it is having some stalling problems. This is how it happens. When I am giving little or no gas and then push on the gas pedal, it will act like it is getting no or possibly too much gas and trys to shutdown. It doesn't do  this at speeds above 30 or so. I have added gas treatment, oil treatment, water remover etc.. But nothing seems to work. Could be the fuel pump I guess, but since it is just an older work truck, I would like to try an easier and cheaper fix first. Do you have any ideas? Thanks so much for your time and I value your opinion.

"Doc" Moore  

Answer
Doc,

  You did not mention if you truck was Fuel injected or not, 87 was the first year of GM's fuel injection on trucks. If it is get back to me and I'll try to point you in the right direction. If its Carburated....sorry I'm strictly a Fuel injection guy.....I'm not even alowed to work on one at work! Get back to me.