[MarCalhoun]

I have a 2003 ford focus that will accelerate when in park or neutral but will not accelerate in gear. Have change the fuel filter, plugs, throttle position sensor, fuel pump, air filter, both oxygen sensors, input shaft speed sensor, catalytic converter, pcv valve and have checked for vacuum leaks.

[TxGreaseMonkey]

If you are saying the car won't move forward or go in reverse, there may be a problem with the torque converter. This transmission may have an issue with the pump shaft splines stripping out in the torque converter. When the splines strip out, the pump no longer turns and the car will not move. If the fluid is suddenly overfull on the dipstick with the engine running, this is most likely the case. To verify the issue a pressure test should be performed. If there is no pressure, the splines are most likely stripped.

[MarCalhoun]

It won't rev up

[TxGreaseMonkey]

Check for codes.