Third gear incorrect ratio on a 2000 mazda protege lx 1.6 engine

Question

I have a 2000 mazda protégé lx automatic with a 1.6 engine. The vehicle started sputtering one day so I took it to a auto parts store and had the engine codes read and it said cylinder 4 misfire. I bought new spark plugs and still had the same issue. The car would get to about 45mph and start acting as if it was in neutral. The rpms would go up but the speed would not. I had a mechanic friend of mine look at the vehicle and he said that the transmission was reading for a incorrect third gear ratio. He thinks I need to just buy a used transmission. Is there a simpler fix than that or is buying a used transmission or rebuilding my transmission my only option. Thanks in advance

Answer 1

What you have is a slipping transmission, Putting in another transmision would be a better option. whether rebuilt or used.