koatic

The symptoms of the problem are that while driving the tach will jump all over nd the engine will hesitate and misfire. since this started I hve done the following
1. swapped ecu's with friend and same problem off the bat.
2. I replaced the entire distributor with new one. ran fine for 20 minutes then problem came back.
3. after a week the engine finally threw a code 1 (oxygen sensor) I replaced the oxygen sensor and it ran fine for about 10 minutes then same problem.
4. I got another distributor. ran fine for bout 30 minutes then same problem.
5. I replaced boshe platinum with denso iridium plugs. ran fine for like 5 minutes then same problem.
6. I replaced my msd 8.5 wires with stock wires. ran fine for about 25 minutes then same problem.

WTF.. the only thing I can think of is my throttle position sensor.
ny clues would be helpful..
and since I replaced my oxygen sensor it is not throwing any codes.