We put about 3000-4000 miles on my girlfriends 97 civic ex (auto) every month; latly the gas milage has dropped greatly (I know the tempature has ALOT to do with that) anyway all the filters and plugs and such are all new. Has anyone actually dont any before and after tests with performance parts? Prices of headers (I ran one for a few years on a GSR i had, never any problems) and CAI are so low on ebay that the milage we put on this thing it would be nice if we could get another few mpg out of it. Anyone have any ideas of what could help with my milage?

 

Sudden drop, what kind of mileage are you getting now?

I got a CAI off ebay with a new K&N filter for like $60, can't beat that.

 

What kind of mileage are you getting?


My '94 GSR'd Civic hatchback depends on how it's driven...I can get up to 32 if I take it easy (lots of highway), but on average...29mpg.

Before I had the swap, my automatic D15B7 got about 28mpg.

 

Have your upstream O2 sensor checked out. If the O2 sensor starts to slow or gets stuck it can effect your mileage.

Also check you tire pressure. In the cold months your tires will lose up to ten psi.

Winter gas will effect your mileage too but just 1-2mpg is all.

 

your tire pressure has to do with it also

 

If it's changed a lot I'm also voting on th o2 sensor being out/defective.