i have a 90 civic with a 94 d15 swap, as of today it started to lose power... i think it may have actually backfired once! anyways , i have a hunch that its the fuel filter, im not sure where its located... could it be the fuel pump? loose vacuum hose maybe? any advice will be much appreciated! thank you

 

it should be right on the fire wall probably right behind ur engine and yes that can lag ur car and make it backfire if ur engine is built u need to at least run 89 fuel or u chance that problem all the time