I am going to chip in, since I just experienced the same problem (it just came back, it happened before in January and "disappeared" by itself).

Driving along I-95 @ 85MPH, all of a sudden the car starts DECREASING speed even though the gas pedal is pressed. It catches on all by itself and takes off.
Sometimes I let it roll to a stop and it idles a little rough, or like crap.
Never had the opportunity to plug in the Duty Cycle meter until today, at exactly the time it happened. Fixed 92.3%

Since 90% is not assigned, the nearest fault is 95% DECELERATION FUEL SHUTOFF SWITCH (MICROSWITCH) which makes sense due to the symptoms experienced.

It feels like a rev limiter does not allow the car to rev up.
Does that sound familiar?

Anyway, I have not had time to check the switch yet, but I am quite confident that is MY problem. And it could be yours too.
I will update when the testing is done.

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1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
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