I just picked up a 97 HX from my dad and drove it down from LA this weekend. Yesterday I changed the plugsm wires, cap , rotor, engine oil, oil filter, fuel filter, adjusted the timing and I adjusted the valves. The car currently has 192K miles on it, It has the CVT Auto tranny

Heres my problem, on my way from LA at the six flags going up hill. I was going 70 MPH steady and I noticed that my RPM was jumping about 500 rpm. I think between 2800-3200 RPM, but once it got flat or down hill it was fine. I also noticed that on a stop and go traffic when i let go of the gas and let the car cruise, I could feel the car tuggin, like it was down shifting. Today on my way to work, I noticed that my RPM jump from 200-800RPM, but it only does this when I'm seatting at a light. If I put the car in Park or neutral it idles fine. Then near my house I noticed that my RPM was jumping whil eaccelerating and then one I hit about 50 MPH its fine.

I'm replacing the fluid this sat once I buy the CVT fluid from Honda.. What seems to be the problem? Transmission going out? Please suggest a place where I can buy a tranny. Would an EX tranny work? Will I need to replace the ECU?