Pull your diagnostic codes. You have transmission problems.will pulse like it will go then lose power then go then lose power and barely goes 30 up and hill and rpms go very high
Mine did this on my Seville and replacing all the plugs and wires fixed it. The Deville I just got was also doing the same thing, but the plugs were new so I replaced all the wires, which were original, and the problem went away.it misses and hesitates when accelerating or going up hills what the heck could cause this????