Your model car has an up shift delay plastic actuator, which is part of the throttle valve, cable mechanism, this complicates the diagnoses.

Driving the car in the “S” mode should let the transmission shift later, if not then the problem can be, the actuator, cable or valve body related.



Adjust the cable as tight as it would go then drive the car at light and medium throttle, do not drive at WOT, you might damage the cable or actuator with a tight cable; if you still have early shift’s, remove the transmission pan, look at the throttle lever, it should be touching the TV plunger, if it doesn’t you have a problem with the cable or actuator. If it does

Have a helper move the gas pedal as you watch the movement of THE throttle lever. The lever should move the plunger " INTO" the valve body. The plunger movement should be the same as gas pedal movement, if it is the valve body is the problem.