I have a 2000 Ford Focus zx3 2.0 DOHC with an automatic transmission. I replaced a TPS recently and upon driving the car I have found that it will not shift from 2nd to 3rd gear or if it does it will slip out of gear. I replaced a shift solenoid and had no luck fixing the problem. As an experiment I disconnected the TPS and the car did not want to shift into 4th gear or kept trying to come out of 4th gear. I reconnected the TPS and it did the same thing as before. I have a feeling that this is some sort of electrical problem, but I honestly have not been able to find someone with a similar problem