i have a 91 accord and im still using the stock fuelpump. when it hits vtec it feels like its slowing down, is that because the stock pump cant feed enough fuel?

also, when i connected my exhaust, an apex ws, the idle was rough and sometimes stalled out. but when i ran it without the muffler, it runs ok. is the backpressure causing some sort of problem?

 

You are very vague describing your set-up.

First I would specify what motor you have...91 Accords didnt have VTEC.

I assume you have an H22 Swap but you dont say that anywhere so for all we know its an F series 2.2 VTEC from a 94 accord w/like 145hp.

Just a suggestion.

PS: if it IS an H22 swap I would say you prob should get the right fuel pump - the F22 fuel pump likely is not good enough (I could be wrong)

 

accord fuel pump is perfectly fine with an h22 swap. unless it was bad to begin with but if you had a brand new accord fuel pump it would be perfectly fine.