I have a 83' Chevy Silverado K10 with a rebuilt 350. It has started cutting out when driving down the road, sometimes for a few seconds. It completely loses power for a few seconds, comes back, loses it again, and so on. It doesn't do it while its changing gears, its when you are cruising. (not while using cruise control, just driving.)It did this once before when the intake was leaking, but its not leaking. I just had a new carb. installed and I thought that was the problem, but its not. The carb. did need replacing anyway. What would be causing this? I was thinking that it may be the fuel pump. Or am I wrong?