Any ideas? My car revs up high fpm no check engine light.

Okay, I have a 1992 Cadillac Seville sts. Has a 4.9ltr pfi
engine.
So far the list of things I've done,
1. A transmission service dropped the pan new fluids filter
and gasket.
2. Octane booster in my gas.
3. New plugs.
4. New fuel filter
5. New catalytic
Any ideas what could be causing me to over rev when I
step on the gas pedal feels like the car could be in limp
mode but there is no check engine light, but I can get up to
100 if I go down hill and it decides to shift past 3rd. If I hit a
hill forget it lol my car slows down over revs won't lose
speed unless I floor it and then it drops slowly and wo t
gain anything. No idea what this could be I have done the
lucas no slip when I did the service and it shifts fine if I
don't floor it no hard shifts notging.