Sorry to sound like a stumped dumb *** but wtf is up with my car.

So far no check engine lights, car has power, it's a 2000 civic Si (b16a2)
I accelerated from a stop sign at normal driving speeds yesterday and it felt like I started off in 3rd. Just passed it off as if I did. Well I left for lunch a while ago and at the stop light my car accelerated wierd just like before, felt like it was in 3rd then about 3.5k rpm's it just started accelerating like it normally would in 1st, I was like WTF. popped the hood just checked the connection of the distributer to the plug wires, checked my fuel pressure guage, both good. took off again and son of a bitch if it didn't do it again. But after the 2nd time today it didn't do it again.. So WTF could be going on here guys. Just so I don't have to answer later the car's got 56k on it I/H/E high flow fuel pump, clutchmasters stage III clutch and that's it .
Thanks in advance guys
Justin
*Note* the car idles fine, has power, sounds no tickier then usual I'm stumped*