1996 Other Nissan Models 6 cyl Front Wheel Drive Automatic 140000 miles
About three months ago the check engine light came on. Shortly after that the engine performance degraded. For example. The engine starts fine with no problems. However, there was a little hestitation in the engine while ideled before shifting to (D) Drive. While accerlation between 25 or 30 RPMs the vehicle whould shift into first gear very hard as if the transmission was shifting while at high RPMs. Second gear would shift much bette, but not normal. Third gear appear to shift normal. Also, the check engin came on and the O/D light blinks.
This eventaully this occured often at low speeds or from stops. The machanic first thought it was the Knock Sensor from the code scanner. After replacing it, the vehicle continue with the same symtoms. Then his diagnostics returned a fault code pointing to a bad TPS. Then he replaced the TPS twice and re-adjusted it twice. He also, have replaced the engine mounts and inspected the transmission mounts. He check the harness to the computer and didn't see any problem with it. He then reset the fault codes. After picking up the vehicle and driving home everything seemed back to normal. That afternoon while driving all the symtoms reappeared. I called the mechanic back and informed him of this and he said that he could not help me. He said it had to be a computer problem. He explained that the computer was not sending a voltage to the TPS when the cars warms up but when the car cools down the voltage start to retransmit back to the TPS. I have now spent over $1000 and still haven't been able to get this fixed. Can you please tell me what I should do next. Since the Speed and TPS sensor has been replace what else could it be.