RPM's & Auto Tranny

[BonesOfSteel]

I noticed that when I first take off with my car my rpm stays high for awhile and then jerks the car pretty good and I was told that is has to do with heating up the cat for emissions. When I am going about 70km and I floor it, it jumps to around 4500 goes up to 5000 then goes about 2000rpm and keeps going while in the same gear. It's almost like it is slipping. It never does this with regular driving only when I am at high speed and want to go. Any help would be great.

[FATHER]

i think those is a normal down shift, when you put the car in driver or reverse it change quikly or take a bout 2 seconds??