sohc engine cut off?

[fetherw8]

i was going down the freeway for the first time in my car yesterday... i was giving it a fair amount of gas to get up to speed once i shifted into 3 gear my engine felt like it hit a speed governer or something, the engine just stopped reving and went back down to idle. i had to shift to 4th to get it to go back to normal. then when i got off the freeway same thing happened only in a different gear. right after i shift or around maybe 3 or 4 grand rpms it would just cut out. what normally causes this?