Have you checked the temperature sensor under the 3-4 intake runner to make sure it is solidly connected and that it is supplying the correct resistance to the ecu? I had an '83 240 that one of the terminals in the connector wasn't snapped in tightly in the connector. The engine did what yours is doing and once the terminal was secured in the plastic housing and snapped on the temp sensor, the engine ran great for years. The sad thing about this was that repair receipts were found in the glove box that showed a poor starting engine was a problem for a couple of years. The previous owners spent plent of money on tows and various parts trying to fix the problem. I hope it is just a loose terminal on your car, John.