Like the title says I put a bad mab header and 3" Dp on and my mpgs dropped from 24-25 around town to 20. This is based on me clocking the mileage not the display. I don't know if I need a tune?

 

cold weather

 

Need tune!

 

tune it? maybe dumping too much fuel

 

lol no you don't

 

Have you been more aggressive in your driving since the header? This would be my guess.

 

For best results tune. But most of the time when winter comes around you will lose fuel (mpg) because **** gas and the gas is e10 blend. In most places on east coast

 

I agree with Chevycobaltss3 Tune it!! Had the same issue, especially in winter season.

 

That was my thought too and I had a bit of a lead foot for the first tank so i babied it for the next two I took it easy just putting around.

 

Try disconnecting your battery so it resets the computer. (aprox 10 Mins)
Then go for a drive on the highway for 1 hour on cruse control at 100KM or 60 MPH

Try that and come back and let us know how that went.

That's what my boyfriend says.

 

i know if its cold my mileage goes to **** lol

 

tune!