Mitsubishi Repair: 94 eclipse trans, rev limiters, rev limiter

Question
My trans is ok for a while when driving normal     When I get on the throttle to kick it down the trans goes to 3rd and only to 2nd if I shift it manually  DEFAULT  how do i tell which sensor or even if its the TCU that is the problem

Answer
Pat,
This may or may not be a problem.  Your car has in it what is known as a rev limiter.  The rev limiters prevents your engine from revving too fast in order to prevent destruction of internal parts.  So if you were going at a speed of 45 MPH, and you step down hard on the gas pedal, you'll kick down into 3rd, but your computer (rev limiter function) may be preventing the transmission to go down into 2nd to prevent problems.  Normally, if your speed is too high, you may not even be able to manually shift it into 2nd gear.  It's not a very good practice to do anyway, and will sharply reduce the life of your transmission.  But if your car is indeed shifting poorly or not at all, I would recommend having a transmission shop inspect your tranny and accompanying eletrical components to diagnose the problem.
Good luck!