Silverado Tow/Haul Mode

oopps that was 3.99 point 9, sorry about the Freudian slip.

In addition to the power and fuel economy loss, ethanol breaks down more quickly than gas, so it's not good for your fuel system if you don't use it within a couple of weeks of putting it in your vehicle. For a lot of people that's not an issue. When I got the new truck, I kept my old one, so I've got two fuel systems to worry about. I only live aout two miles from work, and most of my other driving is in our Escape. So...

We made the same trip this past weekend as the weekend before. I think I've got a pretty good system figured out now. Don't use cruise control, try to stay around 65, varying as the hills dictate, do not use tow/haul mode, but do use range select mode to lock out 6th gear. Using tow/haul mode, after downshifting to 4th for an incline, the transmission was too reluctant to switch back to 5th after clearing the incline. However, not using T/H mode, the transmission wanted to occasionally switch to 6th gear on downhill runs, and then switch immediately back to 5th after leveling out. On state highways where I'm not going as fast, I switch range select to lock out both of the overdrive gears for the same reason. I averaged 9.5 mpg on the trip down. I haven't filled up to know the mpg for the trip back, but it won't be quite as good because of the overall elevation increase coming back from the coast as opposed to traveling to it.

On a side note, we stopped at a rest area to dump tanks. Getting back on the interstate, I didn't have much room to get up to highway speed, and saw a 18-wheeler coming up fast, with traffic to his left so he couldn't get over to allow me room. It was really nice to have the power under the hood to lay the pedal down and get from ~35 mph to ~65 mph in just a couple hundred feet!

Originally posted by pentachris It was really nice to have the power under the hood to lay the pedal down and get from ~35 mph to ~65 mph in just a couple hundred feet!

Very good comment on aging of ethanol.  High concentration levels of ethanol get crudy very quickly.  Burning it in a flex-fuel vehicle won't make much difference if you use it up every week.  But if your flex-fuel vehicle (E85) sits for an extended period, you probably will have a large injector cleaning bill from your mechanic!  I stopped at my Chevy dealer yesterday.  We began to talk about my driving habits with my Silverado.  I use it mainly as a hauling vehicle including towing my Pod. I use a high mpg Prius for most driving.  So the Silverado normally gets a fill once a month if that.  The dealer warned me NOT to fill with E85 unless I burn a full tank every week or so.  He has had a lot of injector work on E85 vehicles that don't get fresh ethanol frequently. He suggested using an gas treatment made for ethanol 'storasge' such as STA-BIL.