I have a 3" intake tube w/ a generic cone air filter. 4-2-1 header and stock exhaust tubing except for a smaller, higher flowing muffler out back.
Aluminum/smaller than stock crank pulley. New Denso O2 sensor 1 week ago.

The car has decent power, but I am getting terrible gas mileage. 20 is my average, and the highest ive gotten is 23mpg. My previous CB7 Accord got 25mpg on a bad day.

Is this because of my additions? The car runs great except for the occasional hard start when it is below freezing outside.

My camshaft seal leaks a little, and I think my rear main seal just went out, cause it is losing about 1 quart of oil every 1.5 weeks. I know these need to be fixed, just haven't had time/money lately. I always keep the oil topped off, though.

So my question is: how do I get better mpg? Is mpg directly effected by the oil leak?



I don't drive it hard except for the occasional 5000rpm pass.

 

The oil leak doesn't affect mpg. Usually when people upgrade their cars they drive it harder and this lowers the mpg's. The more time you spend above 3k rpms the more the timing has to be advanced and retarded and the ecu has to make a lot of adjustments and I believe this makes it less efficient, thus harming mpg's. Just my opinion.

 

If I were you, Id ditch the pulley. Totally worthless. There's a thread somewhere here on how bad they are

 

geez, i can't get lower than 30 mpg in my '99 4 cyl accord (5 spd), 90+% city driving

did you ever drive this one stock (to have a comparison of stock mpg)?