Mine does the same thing.
Its the clutch. Try taping the front of the
compressor with a stick and it will engage.
I'm not sure if the clutch can be fixed without changing thecompressor.
I had the same problem
I bought a wideband and was reading 12, 680ish on the scanmaster with 4kr.
I added 12% via the chip and now 750mv 10.9 wideband 0 kr. Hope it helps.
Hear is a good thread from the prowler board that explains the problem.
transmission imputsensor - ProwlerOnline, Plymouth/Chrysler Prowler Discussion Forum
like I said autozone had the sensors for $15. It seems to hapen more when the car just sits for a while as was the problem with mine.
If its like many chysler trannys there is an input speed sensor and an output speed sensor they tend to just go bad. you can buy them at autozone for $15 each. Usually they are an easy swap just unscrew them with a wrench.
If the speedometer does not work its probably the output sensor.