Mystery RPM/Shifting issue with 2001 Rav4
I have a 2001 4WD Rav4 that periodically “behaves strangely” for the last three to four months. The reason why I use “behave strangely” is because three mechanics (two Toyota specialists) have taken a gander at my car, cannot reproduce the behavior, and cannot diagnose the underlying issue with my car.
At first I would be driving long distances at highway speeds (65-75 mph) in cruise control on relatively flat terrain when the RPMs shoot from ~3K to upwards of 5K. All sense of power and acceleration is lost, the speedometer becomes loose and chaotic, and it seems as if the car is rapidly downshifting and shifting back up. I still have electric power and control of the car, so generally I pull over onto the shoulder of the highway to let my car rest. I turn it completely off. After 10 minutes, I can start back up and accelerate back up to highway speeds and nothing happens afterward. Most times, the “Check Engine Light” comes on, with the code for “Malfunctioning Speed Sensor”. Originally, I thought that it was due to the cruise control, and/or my warm car, and/or functioning at high speeds. However, my car has “behaved strangely” with less than 20 minutes from a cold engine, not in cruise control, and at in-town speeds (~30 mph).
As I said, three mechanics have tried to reproduce this behavior and have not been able to. It is not a loose cruise control (they fixed it to see if it would change anything---and it didn’t, as I told them). Although I have not fixed the speed sensor, two Toyota mechanics are of a mind that the faulty speed sensor behavior is caused by an underlying issue they cannot seem to diagnose.