Tranny or Engines's Fault?

[YW84U]

I've a 91XLT 4.0 with 230,000 or so KM's on it. It's an auto tranny, and has the 3.73 gears, stock tires, and is not particularily 'beat on'.

Trouble is, while driving on the highway for the past few days, I've noticed that at @ 115kph, the tranny keeps shifting back and forth between the overdrive, sending my tach bouncing from @ 2500 to 3000 RPM. As an added bonus, I have a pesky interm ittent CEL that comes up at random.
(the steering column and ignition went up in flames last year, and whacked a bunch of sensors - including melting my JET chip - insurance won't replace it...and it's been in and out of $hop countless times)

I've searched the posts, and believe that my FPR and O2 are the likely culprits for the CEL and sloppy performance.
But is it possible that these items are affecting the shifting of the trans in any way? I've been looking into replacing both items then flushing and replacing with synthetic. The shift points and OD just seem awful....

Any assistance in this regard is greatly appreciated!
Tom

 

[Jon_Herr]

TPS

Have you checked the throttle position sensor?

It is used to determine engine load and influences shift points. So can a low battery condition.

Good Luck!
Jon

 

[gtmazz]

Do you still have the problem with the overdrive? Did you fix it.. I'm having similar problems now on my 91..

Thanks, Jim

 

[YW84U]

What I ended up doing, was I replaced the TPS and O2 sensors a few weeks ago. I found an immediate improvement in driveabilty and performance. CEL no longer comes on, and it drives like a race car.
As for the tranny, it still has a bit of a sloppy shift pattern, though it does not seem quite as noticeable now. I think the next plan is to take it for a tranny flush and tune-up at a local shop ( a Ford tech advised me to flush it last year, but I never got 'round to it...).

But for the most part, the sensors did make a world of difference for the X overall - definitely worth my time.

Good Luck!

Tom