When the transmission is hot after running on the interstate it has a sift problem between 1rst & 2nd. I have to back off on the accelerator to get it to go into 2nd.
Did you check the tranny fluid level.How long has it been since you had a transmission fluid replacement?
Service the transmission and say a silent prayer is all you can do. The car is 20 years old and automatics should be serviced every 30k miles or 40k miles at the absolute maximum.
At some point age and heat will start doing in all of those internal rubber seals and nothing will help.