I have a 92 Taurus GL. I know for a fact that it will go above 85.
Back in 92, they didn't have the capability to put a speed limiter in
the PCM/ECM/CPU. To my knowledge the cpu is just a big relay and
sensor center. The only way they could limit the speed back in that
day is to do something with the transmission. What you are feeling is
not a down-shift at all. It's called the torque converter locking
up. So there are two things that can be done. Reprogram(rebuild) the
transmission. Or............unplug the wire harness. The only
problem I had with unplugging the wire harness is in 2ng and 3rd gear
it shifts violently if you slam the gas. Unplugging the harness
basically unplugs the accumulator pistons, and all they do is cushion
the shifts. Along with that it disables the torque converter from
locking in and out. We unplug them to diagnose torque converter
problems. Do that, and take it for a test drive. On a stock Taurus it
should only reach 120-125mph if your lucky. If you are really good,
you can actually find the right wire on the harness and snip it so you
can keep the accumulators working. However, if you do so..... You
will not have over-drive. You will be taking some fuel economy loss.
If you are worried about doing that, don't worry, I have done it, and
2nd gear - 15.5mph-25.5mph
3rd gear (passing gear) - 50 - 59.9mph.