95 3.4 V6 trans problems

Hey guys Im new to this and a chevrolet ive got a 95 3.4 v6 that drives good but idles funny at times when i drive it hard it will rev to 4000 rpms and fall on its face and wont shift i also get a check engine light on the dash once the light comes on once this happens it ides wierd and the lifters start making noise i just changed the plugs and wires so i know that is not it PLEEEEAAAASSSEE help? im getting tired of messing with this thing