fuel mileage

hey guys my name is anthony i bought my envoy in late 2001 and its still in good condition inside and out people always ask me if its new and i always reply ......yea!------------lol :eek: But my fuel milage realy sucks i get just under 100 miles in the city and under 150 on the highway can...

I took my 04 TB into the shop because the battery would go dead if not driven for a couple of days. Prior to this, I was experiencing some performance issues (rough idle, lower fuel mileage, shifting at higher RPM in low gears, etc). I think the battery might have had a bad cell (brand new 6...