I have a 95 Dodge Intrepid with a 3.3 V6 and I bought off some friends. The transmission felt like it slipped so we put new speed sensors in it and that helped...I started driving it again and now it has trouble shifting up and the engine goes out on me. I checked the tranny fluid but don't know what else to do

 

I'd use a real scanner on the trans computer and engine to see what's going on. otherwise it's all a stab in the dark tossing parts and taking guesses. I've got a great scanner forsale (Snap-on MT2500) it would be perfect for your problem and could even lead to you making money fixing cars