I'm having a issue in my 87 D100 w/ a 318. It has been dying randomly in traffic. I am deploying soon and need help ASAP. Here are the symptoms...

-Idles real low
-Runs and almost sounds like it has a cam (Have to play with the throttle when stopped to get the power or it will just die out)
-After getting on the throttle real hard it will just die and you have to pump it a good five times before it will start up again and usually die with any throttle applied after that if it even will idle at all
-Has only been running good at higher RPMs if it runs at all.
-When driving, it will die as soon as the throttle is let up if coming up on a stop light or turn.
-I was away from home for 6 months and this just started after one die of driving and running fine.
-Always begins to have these issues after the choke shuts off
-Stock 2 barrel holly

PLEASE HELP IM CLUELESS AS TO WHAT IT COULD BE..
Fuel? Ignition?

 

what shape are the steel fuel lines in?

 

Not to bad of shape. It's a Oklahoma truck with 90k original miles.

 

check the fuel filter... sounds EXACTLY like my w150!!! mine was FULL of dirt and that's what was causing it
also if that is the case it might have let dirt into your carb and its starving it of fuel

 

Replaced the filter and cleaned the carb. Still have the same problems..

Does this sound like a vacuum issue to anyone?

 

It could be that too... also, if you have a lock-up torque converter it could be locked in, there is a solenoid that controls the converter lock up and if its not working it could also cause that. there should be a connector near the tranny for it, unplug it and take it for a ride to see if it fixes it and if it does then that's what needs replacing, they can get corrosion build up if not used and like you said it sat for a while.
back on vacuum leaks, if its possible get someone to use a smoke machine on it and then you'll have your answer to that question. if not, can you hear any unusual hissing type noises that could be a possible vacuum leak?
Fuel lines: check the rubber parts of the lines for dry rot, it might not be big enough for fuel to leak out but large enough for air to get into the lines

 

A old timer in town told me to plug off the EGR valve vacuum hose. Seemed to fix almost everything. Odd, but i'm glad it was suggested to me...