I've got a 97 Ex auto coupe w/ ~90k on the Y8. I've recently changed the plugs, wires, fuel filter and seafoamed the engine.. I've got a K&N OEM square and Flowmaster exhaust.. I used to get about 275 mpt(miles per tank).. now even when driving as carefully as possible, never hitting VTEC, and all highway miles i only get about 230-250 mpt ( 25~27 mpg.)


What is killing my mileage? It still has the stock exhaust from header to cat.. and original o2 sensor...

I've thought and thought and thought about what could be causing this but i can't figure it out..

Any suggestions?