Flew to Anchorage the day before thanksgiving and picked up my new F350 Supercab long bed. On the 360mi drive home she averaged 13.4 running in 4x4 probably half the time on some nasty roads the whole way. Next tank was 8.1 running all town with the longest stretch of highway being 2mi. This tank had many idle warm ups at temps around zero. Last tank came in at 7.5mpg with same type of driving and warm ups in the -10° and colder range. At home I park inside the shop but at work it takes a good 15-20 minutes to get things thawed out. I also hit the remote start when out and about at restaurants and what not. With the shock of the 7.5mpg last night I took her for a 100 mile road trip and found it to come in at 13.8 which is totally acceptable. Anyone else find the 6.2 to be thirsty at idle? In comparison my 7.3 diesel only looses about 2-3mpg from highway to town/idle. This 6.2 is dropping over 6mpg.

 

That sounds about right. I always let mine warm up and I see that dropping. Most likely because its getting 0 miles to the gallon the entire time its running before you drive it so that really hammers the average.

 

Yeah I grasp the 0mpg at idle but I have never seen this kind of drop with 5.4 F150, V6 Ford Explorer, 390 Ford or 96' 7.3 powerstroke. Seems to use twice as much at idle.

 

I have had a couple 7.3s and, yes, they did use quite a bit less fuel at idle. My V10 seemed to use a lot idling in the Chicago winters at idle as does my 6.2 so I just chalked it up to it being a gas/vs diesel.

Your gas to gas comparison is a 5.4 vs 6.2. 6.2 is a little larger, has 2 spark plugs per cylinder. It may even be set up to run a little richer at idle.

I will be anxious to see if people have any other ideas. I have been letting my 6.2 idle less as it gets cold.

On the plus side, I got 19 MPG empty on my last freeway trip going 130 miles

 

How is that even possible? All downhill? On completely flat ground with my cruise set on 55 the instant mpg shows maybe 14-15 and set on 65 it shows 13-14. Lower than 55 seems to make minimal changes.

 

Ha. Yeah. I was remembering incorrectly. My old truck 5.0 f150 could do 19 on the freeway.

Just checked the image I took a while back. 16.8 mpg was the trip in the 6.2 (I have 3.55 gears) I am referring to. That was with no idle warm up time. Just start, reset mpg meter and go. I checked it once I got to my destination.

Still not bad for a big pig of a truck. I don't really worry about MPG though. When its empty, I fill it up.

Some of the new dodges and GMs with the cylinder on demand are seeing 20+. Weird that ford is just making their engines smaller (forcing them to work harder) rather than going the cylinder deactivation route that seems to work really well.

 

3.55 gears must be a 2wd or F150? Thinking when I was looking at specs on 4x4 F350 there was only something like 3.73 or 4.30.

Like you I don't really worry about it. If I wanted mpg I wouldn't be driving a F350 with a 6.2 gas engine. I am just curious if others have found it to be thirsty at idle.

 

Yeah. Totally getting my wires crossed today. F150 was 3.55. My 350 is 3.73.

Geez.

Thirsty at idle? 6.2? Yes. V10? Mine was. 7.3? Mine was not. Not sure why. Different engines.

 

So that would translate your 16.8 to 8.61mph which is believable.

 

Hmmm. Something may be wrong with your engine? Bad gas? Needs broken in? I towed a car hauler through the hills of WV and average just over 11 mpg.

 

Yes Crumm... they are thirsty. I was out with my wife last Friday, pulled into the bank with 12.9 mpg showing and left it running with my wife inside. When I came out maybe 6 or 7 minutes later, it read 9.6! I hate watching that calculator - that's stuff I rarely ever considered until I got this truck. My '08 Diesel had a Lie-O-Meter too but I never noticed that kind of drop!!!

 

3mpg drop in seven minutes is a definite sign of thirsty idle. Do you remember how long it had been since a reset?

 

Mine guzzles at idle as well.

 

Only a couple of days... maybe 85-90 miles. I need to do a real calculation by hand on my next tank full and see if that computer is for real - I can't believe that it could burn that much at idle!!!

 

That recent of a reset would make idleing drop the mpg faster than if it had been several hundred miles since a reset.