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Number three with 97 Mondeo Transmission problems

2K views 2 replies 1 participant last post by  NKJensen 
#1 ·
I've read the two threads about other 97 Mondeo problems.

My car (2,5L V6 automatic stationwaggon, originally sold in Sweden) switches strangely when starting from a complete stop, if I run the engine round 1500-2000 rpm constantly. Higher engine speeds does not show the same problem.

It seems as if it shifts very quickly to 3rd or 4th then changes its mind and downshifts again. This may repeat once or twice more.

It doesn't do anything strange above 30-40 km/h.

The gearbox has been completely renovated recently. We showed the problem to the transmission guy, who said that it wasn't his fault after trying several tests. He then took out the gearbox, fitted another one, saw the same problem, and fitted the renovated gearbox again.

If I hold the breake hard and revs up the engine to 1500 rpm and then release the accelerator (still keeping the brake pressed), two things happen depending on the position of the gear selector.

In pos "1" or pos "2", the engine revs up, and then down, with no strange sounds or bumps.

In pos "D", the engine revs up - no bumps - but during the decending rev phase, the car makes a significant bump around 1000 rpm.

The engine speed is ZERO during both above test.

The local Ford dealer (authorized by Ford) did run "the computer" on it and it shows nothing wrong. I don't know if "the computer" can read error codes from the engine control system as well as the transmission control system (I'm told that the car has two boxes, one responsible for the engine the other box controls the transmission)

Another poster talks about a VSS, it may have been replaced:

Ford replaced a "speed sensor", which was accessible from below the car (I wonder why the speedometer wasn't wrong?), this caused a very minor change but not a complete cure.

Another poster mentions an electrical multiplug - which I can't locate anywhere.

Any ideas welcome,
Best regards,
Niels Kristian Jensen
Denmark
 
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#3 ·
Replacing the TPS didn't work, but the throtte flap housing was very very dirty with some tar-like substance. The engine seems more responsive to gas pedal movements now, but the erronious shifting is still there - around 1500 rpm on the engine, when starting from complete stop.

Would it perhaps help to clean the MAF sensor (mass air flow sensor) ?
 
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