95 jetta intermittant hesitation

I am desperate and need help. I have a 95 Jetta, 2.0 with an intermittant problem. It will be running fine one minute and then bogg down the next, it does it hot, cold and at any speed. The MIL(Check Engine Light) will come on and then all of a sudden everything clears up and the MIL will turn off. I have gone to 2 different shops that specialize in VW and they say the only codes that come up are for the cam sensor and crank position sensor but after some research on alldatadiy.com those codes are supposed to come up when the engine is not running and a diagnostic computer is hooked up.
I have checked most of the wiring and replaced the following parts within the past year and half: cap, rotor, wires, fuel pump, fuel press regulator, ECM, coil (with spark mod), O2 sensor, fuel filter, MAF, fuel pump relay and crank position sensor. I am stuck!!! I hope You can help!!!

Might want to check the tps. You can disconnect it to see if it still happens. It's hard to tell when it's intermittent. When it was connected to the computer, the sensor might have been working properly at the time.