Poor Fuel Mileage after TPS & Vacuum Hose Mod
I recently did the TPS adjustment and Vacuum Hose Mod on my 2008 V with 14K miles. The engine is all stock with no other modifications. After doing these mods, my fuel mileage dropped significantly. Prior to these mods, I would usually get around 200 miles or so from a tank of fuel, now I am only getting around 160-175 miles.
After my first tank of fuel, and noticing how bad the mileage was, I set the TPS back to stock setting, hoping fuel mileage would improve because after reading some of Invader's posts, he discussed how fuel mileage would drop a bit because you are adding more fuel to help smooth out low throttle inputs. I am nearing the end of my second tank and I only have 115 miles on the tank and my fuel gauge is reading 2 bars.
Does the Vacuum Hose Mod decrease fuel mileage? Does the TPS mod also decrease fuel mileage too? Or, can I blame this decrease in mileage on winter fuel with ethenol added. I always run 93 octane and in the past, could get well over 225 miles on a tank (roughly 50 or so MPG).
I have not adjust the valves, nor have I sync'd the throttle bodies. If I do both of those maintenance jobs, should I see an increase in my mileage again???
I have been riding with my top box more lately. Could this be an issue for my drop in MPG??
Overall, the low speed jerkiness and surging has been eliminated by both of these mods, but I am kind of bummed that my fuel mileage has dropped.
Perhaps any insight from Invader or any other member who has done these mods would be appreciated.