Hi, I recently got a 1999 S80 T6. I've been loving it so far, but the gas mileage seems a bit low (14-16 mpg average) from what I've seen. I have replaced the spark plugs, fixed the CEL (evap leak), and checked all the tires out for the correct pressure. I don't really know what else I can do to solve my problem. The car stutters when cold, but besides that it drives well besides crappy shocks. I also replaced the ETM with an upgraded model that shouldn't break, don't know if that applies to anything here. Any help would be great, thank you so much!