It may be your EGR valve....

 

Everybody who lives in cold climates claims they add stuff to the gas in the winter and it makes the mpg drop a little.

 

Ehh, I don't know about that. Wouldn't explain why the gas prices always drop during the Winter.

 

its true, they add chemicals to keep the gasoline from gelling up, the gas is not as efficient in the colder climates in the winter.. and the excessive idling doesnt help.. it has to be warm to drive or stuff breaks

 

Check the diagnostic codes. With the engine off, turn the key to on, off, on, off and on. Watch the Check engine light and count the flashes. On, pause, On, On would be a code 12. Last code is 55, end of message.

 

True there is more oxygen during the winter, but I think they lean the fuel mixture up during the winter. You also have a good 5-10 minutes before you engine reaches it's normal operating temperature.

 

I putted an fuel system cleaner but for now... after 90 Miles, i have the same MPG... 9.8 MPG

 

I got the code 12 so on pause on on what does it mean?

 

Guys?

 

Code 12 says the codes were cleared. Maybe you took the battery out, or the batt died, or some one cleared the codes before you bought it...????

Dealers, garages charge about 100 or up for a code scan. Go out and get (or borrow) a code scanner that gives codes, definitions, and some sensor readings. I have the CP9185, I love it. Read the raw data and see what the 02 sensors say. A bad 02 sensor wont stop your engine from running, but it will cause the comp to dump fuel in the engine, resulting in low low low fuel mileage.

A good scanner, like the CP9185 i got will run about 185 to 200 us dollars. You fix your car twice and its paid for. The 02 sensor, maybe 50 to 100 dollars. The pain killers after the dealership gets done swapping parts cuz "theyz be old" will drain your bank account. Mechanics and divorce lawyers say the same thing "It'll only cost a little more than you have in the bank".

btw, this only applies to OBDii (1996 or newer vehicles.) For older, you'll need to get a special scanner or a volt meter and crack the books.