HI all: I'm hoping someone out there either had a similar experience as I did and successfully resolved it, or one of you is an amazing mechanic that knows the resolution to this...
We have a 1993 Mitsubishi Montero. The problem we're currently having: the overdrive will disengage when it shouldn't. We first noticed that it wouldn't engage until the speed reached 65mph, regardless of the RPMs. If you dropped below that speed, it would go out of overdrive and then if you went back over 65mph it would re-engage. (There is a button on the shift stem that if you turn it off, it won't go into overdrive at all. But this button is in the proper "on" position.)
So we took it to a Mitsubishi dealer to have their mechanics work on it, for which I spent $650 - and yet it still is not working right.
The mechanic found that "throttle position sensor was way out of range. Throttle body is carboned slightly on the inside and the idle air control motor is inoperable."
So they did the following - parts and labors listed here: 1) Induction system/throttle body cleaning, 2) Carburetor cleaner, 3) Servo kit, throttle body.
We got it back from them and it seemed ok for a couple of days. Then we'd notice that when we were on the freeway and starting to go down a hill - regardless of the speed or RPMs, that it would pop out of overdrive. And then it could take miles (or never) for it to go back into overdrive. It seems that there is very little pattern to what is going on now, but it clearly is still not working right.
Before I go back to the dealer - and have them charge me more $$$ for diagnostics - I thought it would be helpful to get some insights/input/advice. Any of you brilliant mechanics have any idea what's up?
Thanks.
Keith