Thankyou Filp. I'm still researching the links you provided. WDBCB20 yes the kickdown switch was checked and appears to be operational.

Currently we checked first the vacuum. We found that both the vacuum amplifier/transducer on the driver side fender and another vacuum module secured to the radiator reservoir responsible for EGR operation where both leaking vacuum. These leaks where audible. Vacuum to the transmission module coming off the vacuum transducer was around 8 hg. Car was sluggish. Both parts where replaced with units from a donor at a junk yard. Both hold vacuum without much of a leak and there is now 15 hg of vacuum going to the transmission. Going on a test ride, the car takes off like a bat out of hell. Great pickup. Problem is it won't shift to 4rth.
Accelerated car to about 55 mph and was still in 3rd. When you let off the go pedal, it slows down (engine braking) just like that of a manual trans. This points to the K1 & K2 piston. Have a replacement piston kit on order and should be in shortly.
Thanks for the help so far. Will keep you posted and also to what the fix is.