I agree with the speed sensor diagnosis, just did that repair on my 95, all the same symptoms. Mine is a mechanical cable, if yours is really electronic perhaps that is why the manufacture date changes the needed part. Shouldn't take more than an hour labor although that experience is with the mechanical version.
Simple fix in the meantime is to shift by hand, starting from 2 is OK and once you get up to speed it should stay in 3rd gear.
