1995 Plymouth Voyager Bucks like a Bronco. Sometimes

It runs worse when warmed up, even worse after a few miles on the highway. It bucks, it is nonresponsive. If you tickle the accelorator with your foot it responds for a few secons. The error codes are
12 21 32 51 21 55

Any help would be appreciated. It does leak oil and transmission fluid. They are kept at appropriate levels though.

Thanx again
Rich