bad gas mileage and exhaust odor

[FASTLLS]

haha thats exactly what i do

I know.. It's hard to resist!

hmmm.. makes sense i guess just dont understand why it fluctuates from fill up til fill and why it changed when i replaced the battery. im gonna unplug the battery tomorrow for awhile then fill up and see what it gives me then

Probably because it resets your mpg and when you start it, your not moving resulting in a really low mpg and miles till empty..