3g hemi gas mileage

5.7 hemi said
Have I not figured the mileage out right??? 74.8 divided by 5.391 equals 13.87,so how has anybody got any different??? Thinking of getting a spun universal cat and running the rear o2 sensor just for ***** and giggles. So far I cant find any company that will sell into Cali.....that is chicken ****!!
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Do you have a SES(service engine soon) or CEL(check engine light) hooked up? If you are running a stock computer,and no cat,and no 2nd O2 after the cat,you are going to run pig rich. You NEED that 2nd O2,and if you are not going to run a cat then you need this http://www.gtimotorsports.com/product/O2-Sensor-Spacer/Default.aspx?gfid=p653 or something similar to "trick" your ECM.