Auto transmission sluggish 3rd to 4th
Automatic Transmission May Not Shift Correctly at High Mileages on Toyota Corolla
At higher mileages, (125,000-150,000) the automatic transmission may not shift correctly. This can be caused by the throttle position sensor being out of adjustment or a shift solenoid needing to be replaced. Typically the transmission does not need to be completely overhauled.
309 people reported this problem
25 model years affected
Average mileage: 169,682
Beyond the information weekend-warrior provided, if you haven’t changed the transmission fluid regularly, that could make the problem worse.
The main input to the transmission is the vehicle speed. Modulating inputs are the throttle position & intake manifold vacuum, so those sensors should be checked, along with the vehicle speed sensor. Shift solenoid problem possible, but imo the least likely. Finally, along w/the good advice above to verify the fluid in good condition and level correct, make sure all engine and transmission diagnostic codes, current and pending, have been addressed. A proper routine transmission service could only help.