UltraGauge for optimizing your fuel efficiency

I've learned so much about how to get better fuel efficiency from my truck by using this device that I figured it was time to share. I think there are similar devices but I can't speak for them. It's called an UltraGauge and its an aftermarket scan tool that hooks into your OBDII port (same thing repair shops plug into to see why your check engine light is on). It can display anything that your car's computer is measuring. Car geeks can monitor O2 levels, fuel pressure, torque, etc but I care about fuel efficiency. UltraGauge

It will measure instantaneous mpg, mpg per trip, mpg forever, etc. I have mine set up to show MPH, instantaneous MPG, short term MPG and overall MPG. That way I can play with my driving and see an immediate effect. I can also try to hit a goal of getting over 32 mpg for a trip to town. The reason I monitor MPH is cuz Toyota speedometers under report your actual speed a bit (from my experience).

It plugs in easily and you can get mounting brackets. I just have it laying on the dashboard and it's never moved or been a problem.

Advantages to buying this gauge device:
-Even if your car measures instantaneous MPG it often stops at 100mpg. I know that sounds silly but it's very helpful if it goes all the way up to the actual number. I learned this is important when coasting down off ramps. I always heard that on new cars if you leave the clutch engaged (or foot off the gas on an automatic) the engine will cut the fuel to the engine and you'll get better mileage than if you idle in neutral. When I tried it at 70 mph with the transmission engaged I got 120 mpg. When I hit the clutch I got 220mpg. Now I know (on my truck) to always go into neutral or hold the clutch when coasting.

-It can read those trouble codes so you may be able to avoid a trip to the shop.

-You can set up warning alarms for any of the gauges.

Some things I've learned. This is on a stick shift 2013 Tacoma:

-If you're cruising along at 40 mph and you move the gas pedal the least amount you possibly can, it will change your mpg by about 5. No joke. So I can easily be driving along and not pay attention to my driving and get 25mpg. Then just let off the gas a tiny amount and my mpg bumps up to 35.

-Hills are your friends. I'll deliberately use a bit more gas to get up a small rise and then hit the clutch and coast down the other side. 10 seconds of getting 13mpg followed by 30 seconds of 120 mpg works out nicely.

-Driving like a grandma is not always the best. I used to nurse the truck up to speed for quite a distance but now I've found it's better to speed up quicker and then let off the gas (spend more time cruising at 40mpg). The amount of acceleration mpg difference (on my truck) is:
Grandma acceleration = 16 mpg
Modest prompt acceleration = 13 mpg
Teenager acceleration = 9 mpg

-Use clutch when coasting down off ramps and down hills. Engine braking in the mountains would be neat to experiment on with this tool.

-Town driving is an opportunity. You learn to coast a lot more when you can see the results.

-Defrost uses the air conditioner (which gives you lower mpg). But on my truck the compressor runs for a bit and then stops so the mpg cycles.

-Setting the vent to head/foot and cold (but not AC) would still run the AC on my previous truck (Ford Ranger). I can't remember if it does on the Tacoma (don't need AC much here)

-Drafting semis really helps the mileage. Even being a normal safe following distance behind a semi can bump my freeway mileage by 5-10 mpg. Being two car lengths behind is even more fuel efficient but possibly not safe.

-Drafting any vehicle, especially pickups, vans, SUVs or things with non-aerodynamic shapes also helps your efficiency. If you're cruising down the highway and get passed by someone going a couple miles per hour faster than you, it's more efficient to speed up and draft them than it is to curse their speeding and feel self-righteous.

-Highway driving with AC on is clearly worse for my mileage than the windows open (yes I know this is the opposite of what they say on tv)

I might have figured this out without this tool but I doubt it. The instant feedback was critical for me to learn. I'd recommend them and they're only $70.

I really wish I could use one of these, but not a one of my vehicles has a standard OBDII port. The ford comes closest, but is listed in the incompatibility list for this product as well as the seemingly similar Scangauge II.

-Drafting semis really helps the mileage. Even being a normal safe following distance behind a semi can bump my freeway mileage by 5-10 mpg. Being two car lengths behind is even more fuel efficient but possibly not safe.

I do this, but I've been brake-checked a few times. Exciting... and unnecessary, since I let them get away if they politely flash their lights. Drafting for hours on end is pretty wearing compared to regular driving, but it's hard to resist given how big the difference is, though; tucked in behind a semi, my EGT gauge and right foot tell me I'm only using about 50mph worth of fuel to do ~65mph. Given the non-linear nature of fuel efficiency and aerodynamics this is pretty huge. Unfortunately with the very un-aerodynamic nature of my van I need to be really close, like <15ft, or the draft bounces me all over the place.


I bought a a different multifunction gauge for my E350 PSD, an Aeroforce Interceptor. Has some Powerstroke specific features that I wanted, and was listed as compatible with the oddball interface.
Don't buy this one! Many of the listed features do not work; the website advertises many features, but in the small print lists exceptions; nothing like as clear at the ultra-gauge site. More annoying, some of the features that specifically *are* supposed to work on my vehicle, don't. Furthermore, I had 4 failures(twice each with twin gauges) in a year. The customer service could be worse, but it could sure be better, especially for the much higher price they charge.

One reason semis don't like being drafted is it cuts their already low fuel mileage further. Another reason of course is safety. Wish that gauge would work on my 78 F350!

I have a hard time believing safety is the number one concern of a semi driver who reacts to a drafter by brake-checking them! Like I said, I always let them go if they flash their lights... so the brake checks have been with no prior 'go away' signal.

One reason semis don't like being drafted is it cuts their already low fuel mileage further

Do you have a source for this? I have always believed the opposite, as my smaller vehicle should act like a boat-tail of sorts, lessening the size of the dead-spot and resultant draft, which is a big part of their bad fuel mileage. Part of why I'm fine with people drafting me...


I've been interested to observe the folding aerodynamic improvement panels on the rear of some semis; I can feel a huge difference in the air turbulence behind these trucks, much smaller dead spot. Seems like a great addition to me... well, except from a drafters perspective!

Mike Jay wrote:

-Hills are your friends. I'll deliberately use a bit more gas to get up a small rise and then hit the clutch and coast down the other side. 10 seconds of getting 13mpg followed by 30 seconds of 120 mpg works out nicely.


-Use clutch when coasting down off ramps and down hills. Engine braking in the mountains would be neat to experiment on with this tool.

Momentum is the key, but letting the engine coast in a high gear actually uses no gas at all.
When you put the clutch pedal in the engine runs on idle which uses roughly about 0.25 a (us) gallon per hour, or a litre per hour.
So it depends on the hill, the right gear downhill keeps the car speed constant while using no fuel.

Also, pulse and glide works very well to lower usage. (It's annoying for the person behind you though!)

Rus, I have always been told that when you coast in a high gear the engine computer cuts off the gas to the engine and your momentum keeps the engine turning without the need for any gas (ie engine braking without fuel). I drove that way for a while until I got the gauge and learned that for my truck it did not operate that way. My example of the off ramp is how I learned. I'd get 120 mpg coasting in fifth gear and 220 mpg coasting with the clutch in. This was at freeway speeds so in fifth gear I was turning about 2000 rpm. In idle it was closer to 700 rpm. If I was coasting in gear at 30 miles per hour maybe the engine speed would have been below 700 rpm and the fuel used would have been lower than in idle. But in no case have I found a situation where the engine uses no gas, unless it's turned off That's for my 2013 Tacoma, I'm sure it's species dependent.

Pulse and glide is great but you're right, it would annoy the person behind you. If I can time my pulses and glides to the small hills on my drive to town, I can get a similar benefit without the speed changing as much.

I wish vehicles came with a cruise control that focused on fuel efficiency instead of precise speed. For instance you could set the speed to 65 mph and then it does whatever it can to maximize efficiency while staying between 62 and 68.

While I haven't got a scanguage to advise me about the resulting mpg, my vehicles all act differently when attempting coasting. The manual truck, I can feel acceleration, or decreased deceleration(depending on on how steep the hill is) when I put the clutch in vs coasting in high gear. I can coast a lot farther with the clutch in than in high gear.

My E350 PSD, with an E4OD auto, seems to think I want it to provide engine braking if I try coasting, to the extent that I need to provide some throttle to keep speed up even on fairly noticeable downhill slope. However, if I tap the brake, it will drop the engine braking until the gas is next hit. So, on a long downhill without hitting the brake it would hold me in OD at whatever RPM results, and if the slope isn't steep enough to keep the RPMs up I will have to give some throttle... but if I tap the brake once, I will instead get a nice high idle RPM of around 1200, and I can coast much farther/faster.

I wish vehicles came with a cruise control that focused on fuel efficiency instead of precise speed. For instance you could set the speed to 65 mph and then it does whatever it can to maximize efficiency while staying between 62 and 68.

This would be great, especially for relatively flat areas. I'd still probably use the pedal in mountainous regions, since there will be times I want to accelerate to 75 as I can see a huge hill looming, or settle for 50 with OD off as it keeps the EGTs in the happy range... but an MPG-centric cruise control would be awesome on a long prairie drive.

On the relatively flat highways around here I find myself using cruise and then bumping the cruise knob up or down as I go over rises. I bump down 1-3 MPH as I go up a rise (to keep MPG in a good place) and then as I go down the other side, if I see the MPG getting to around 100 I bump the speed up. I can definitely feel my engine start to engine brake when my MPG gets over 100. By bumping the cruise up a couple MPH it keeps me in the 60-80 MPG range and I am ready for the next rise.