94 civic ex with d15 block and jdm 1.6 vtec head

Driving on 275 and was in 4th gear and about 4.5k rpm and it started to bogg and will not go over 5k rpm. Stoped at the store and checked my oil (oil is fine) So get home and check the dizzy and all wires everything checks out ok. Also when i start the car up it goes over 5k then about two mins of running it wont go over 5k again. So what could be doing this.


any help would be greatfull