I had the same issue with my truck and after going over everything two or three times with no improvement I finally figured it out. In my case the wire to the distributor had corroded and broken inside but maintained contact. When I stabbed the throttle the dizzy rotated causing the wire to momentarily separate. It would almost kill the engine until the dizzy relaxed to its normal position. I could accelerate slowly without a problem.
Just one more thing to check.
