Plymouth voyager SE 1995 turns over/will not start! any thoughts?

Heres the thing, a family member "accidently" drove the van in 3rd gear at 70 and 75 mph for oh maybey 50-70 miles. This person then put it into drive after noticing... the oil pressure gauge was way up.. but the van did not heat up. Drove fine for approx. 500 miles. Began making a "clunking sound" and jerking, now it does not start. Turns over, has spark etc. won`t start. Is it the trans or could this be a fuel pump? Until this the vehicle has been taken well care of. Any thoughts?