Misfiring?

I Drive A 1994 Chevy 1500 Auto, the problem is that i hit a big bump going pretty fast and ever since that when i step on the gas in drive it starts off alright but when its getting ready to change gears it kinda misfires and cuts the gas off and back on. This only happens when i put the pedal about 50 to 100% all the way down. any suggestions?

thank you.