Need the experts.
96 is when they started the OBDII. id check the cats, but definetly not drive it to long in case the transmission is going out, you may be able to save money if it is the transmission. you dont want a $200 part breaking $1500 worth of parts.
Start with you basics and check the fluid. I had many trucks in the army put on the deadline list with trans failure because the fluid was overfilled. Make sure its at running temp. Also contaminated fluid can cause shifting issues. Then check for loose or broken connections. Also follow the how to and pull your cel codes. We can help you better if we know what you computer is yelling at you every time you drive.
I had the same problem you're having but I just changed the plugs and wires and that was it. I posted on the forum about it and a bunch of people told me it was some complex, expensive problem. Start with the simple stuff like a tune up, fuel filter, etc.

