rpm gauge wont go over 4k

[blu2fourty]

when i rev my car on neutral above 4k the rpm gauge will stay at 4k and the needle will act like 4k was redline. on every gear also. never happen before. if i'm flooring and i hit over 4k the car doesnt run smooth like its struggling. if i'm not flooring it hard over 4k the car runs pretty good.

the car is a s14 with a redtop sr. i think a part of the problem could be i'm still on a stock fuel pump(got to double check if its stock) but i don't see how that would effect the rpm gauge.

any help would be nice.

thanks,
jon