car wont rev..... no power?????

[erollinc]

my 92 ka24de will randomly lose all power and stop revving at like 4K and then 10 min later randomly desides to run good..... thought it was a clogged fuel filter but put a new one in and its still slow as hell half the time i drive it , i have a fuel pump on order and im hoping thats the problem ...... do you guys think im on point? or am i just wasting money?

thanks

[Poatree]

sounds like it could be alot of things, let us know when u get that pump installed