Fuel Mileage Issue

[jwach]

I searched through the forum but didn't come up with what I was looking for so if anyone has a link that would be great. Anyway, Over the last month my highway mileage has dropped from about 29 to about 20. The car runs totally fine otherwise and doesn't throw any codes or make any strange noises. Spark plugs are on my list of things to check except its about 10 degrees today Any other suggestions?

[ericspecullaas]

yeah your fuel pressure regulator is bad. that would cause your mpg to drop im guessing your car smells like fuel under the hood

[jwach]

Nothing seems strange under the hood. How would I test that?

[Scottydoggs]

winter fuel maybe killing your mpg?

[ericspecullaas]

take it off and smell it were the vac line hooks up. if it smells of fuel then its leaking and the flooding your motor

[jwach]

Maybe a little bit but I always get atleast 25 on the interstate and I've had the car 3 years now. I just haven't came up with anything thats "wrong". I put new coppers in about 5k ago and they have been great so i doubt its them but seems like a good place to start.

[Scottydoggs]

soft tires maybe too. im sure its cold there. also letting it sit and warm up will kill the mpg on the dic.

[jwach]

The last trip was 300 miles straight shot and I calculated at the pump not the DIC. Ill check the fuel pressure regulator too. Thanks!

[Scottydoggs]

do you always do the real math? or was that the first time? cause the dic is not 100% accurate at all.

[Slick2500]

Have you tried turning it off and on again?

[jwach]

I do the real math almost every time I fill. I don't trust the DIC.