I have a 1999 Suburban Diesel K2500 that was averaging about 16-17 mpg over the last 18 years. It has 170,000 miles on it now. Last year I put in HotShot Secret Stiction Eliminator Oil Additive with the oil change and again this year. I am now getting 19-20 mpg. It isn’t a big change but it is an improvement. I believe it can be put in Gasoline Engines as well. The rest of the vehicle is bone stock. Their phone number is (800)341-6516. Give them a call and see if it works as well in Gasoline engines. I think it is the cheapest solution to get a 10-20% improvement in mileage in a rolling dinosaur.
My 2017 VW Golf Sportwagen 4Motion gets 30-38 mpg, but you can’t haul 9 people and 1,000 pounds of luggage and tools, or tow my boat with it, and get pretty much the same mileage, for all the (small) minded that commented so far.
If this miracle additive worked as you state, they it would be part of gasoline, added by the refinery.
Sorry, but this is too subjective for me. Reminds me of the “Brown gas” mods. Many users claimed a MPG improvement. But lacking a true double blind test, I have to believe the users were driving more conservatively, unconsciously,
There’s not much you can do other than checking for and addressing diagnostic codes & keeping the routine engine maintenance up to date. And check to make sure the engine is reaching the specified operating temperature within 15 minutes of driving, you might discover you have a faulty thermostat.
You’ve received good recommendations here, most addressing driving habits and the importance of keeping the vehicle well maintained. But, in summary, the bottom line is that you’re driving a monstrous vehicle with the aerodynamics of a huge brick and definitely not designed for fuel efficiency. I think your only choice short of replacing it with something more efficient is to review the recommendations, apply those that you’re comfortable with, and accept he mileage you’re getting.
My opinion is that trying to modify the engine is foolhearty and may end up costing you big time.
Tires, already suggested, can help. I’ve seen my own mileage go down and up just from changing tires. But remember that you need something compatible with your driving environment. Low Rolling Resistance (LRR) tires might help your vehicle, but if you have to deal with bad winter weather they could also get you killed.
Sincere best.
My solution to your problem is: “Do nothing”. If you are keeping the engine in good running condition, keeping the tires inflated and practicing good driving procedures, you are maximizing your mileage.
You transport 6 kids. If you swapped your Suburban for two Corollas, your wife drove one Corolla and you drove the other, and put 3 kids in each Corolla, the gasoline consumed would be as much as if you all piled into the Suburban. Besides, you would have the expense of insuring 2 vehicles instead of one.
If you are thinking of swapping for a minivan, minivans are on a car chassis and don’t make good trucks.
I have a similar situation. I frequently transport musicians and their instruments. I have a Toyota Sienna minivan. Now, we might be able to take two more economical cars to gigs, but we would use more fuel. I tried to convince Mrs.Triedaq I should have a Mazda Miata to drive when I didn’t need to use the Sienna. Unfortunately, Mrs. Triedaq saw right through my intentions and calculated how much we would lose by adding another vehicle.
What I am saying is that the Suburban seems to fit your needs. It is probably the most cost effective for you even with its 16 mpg.
I knew a couple that went out and bought a Chrysler Cordoba with the lean burn engine back in the gasoline “shortage” of the 1970s. They worried about gas mileage after the wife had a job change with a longer commute, so they traded the Cordoba which was less than a year old, for a new Audi Fox. The problems with the Audi consumed every penny saved on gasoline and the depreciation lost on the Cordoba really set them back financially.
I made the same mistake in reverse. I was driving a Ford Maverick in those days. I had a colleague who was a single man who purchased a new Mercury Grand Marquis. He died less than a month after buying the Grand Marquis. I was offered the Marquis at a very good price, but I turned it down as I was worried about gas mileage. I would have had a wonderful car at a great price and the lower gas mileage on the Grand Marquis would have been made up by the money I would have saved on Preparation-H I needed from riding in the Maverick. I did replace the Maverick with an Oldsmobile Cutlass Salon which did get better mileage than the Grand Marquis, but I never made up the savings on gasoline over not snapping up the Grand Marquis at the price it was offered to me.
You have 6 kids, a wife and you need it for your job. But how often do you drive it when you don’t need all that capacity, say a run into town just for a gallon of milk? Keep the Suburban for when you need it and do most of the things listed above, but also get a small economical vehicle that gets 35+ mpg for those times when it is just you, or your wife running an errand. I’ll bet you will find that half your driving could be done with the small car, plus the Suburban will last twice as long.
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How often do you all go to the same place at the same time?
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Do you have more than one driver in the family?
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Is this your family’s only vehicle, or is there a second vehicle?
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What kind of work are you using it for?
If the answer to question 1 is “rarely” or “once a week,” the answer to question 2 is “yes,” and the answer to question 3 is “we have a second vehicle that holds 3-4 children,” I question whether you really need the Suburban for everyday driving.
…by driving slower (the speed limit in the slow lane).
…by following commercial trucks at a safe distance when driving on the highway.
Would the additional costs of car payment, insurance, and maintenance be less than the amount of fuel costs saved in this scenario? Without crunching the numbers, I wouldn’t take for granted that the answer is yes.
Should I upgrade to a more fuel efficient vehicle?
The last time we had $4/gallon gas, the financial experts recommended against trading in a vehicle just to save money on fuel, because the costs of upgrading exceeded the money saved from using less fuel.
@Whitey, you have to compare total costs to total costs, not just the total costs of the additional vehicle to the gas saved by the additional vehicle.
We don’t have specifics on the Suburban as to age/miles. If it is near its service life, this might not be a good solution. However if it is at say the halfway point or less, then it can make economic sense. If @thomashilleke has paid off the Suburban, the small economical vehicle can extend the remaining life of the Suburban where just this factor makes it cost effective.
A new Suburban would cost somewhere north of $40k. A small econobox can be had for $20-22k. So if the Suburban currently is 5 years old and has another 5 years of expected life at the current rate of use and the econobox can be used for half the miles currently accumulating, then the Suburbans life has just been extended by 5 years for half the cost. This works out to about a break even just on ownership costs. The gas savings puts it on the plus side, but insurance could cut into that severely. Maintenance costs should even out.
The OP will have to determine if this is a workable route for him, I was only offering an alternative.
Agreed.
Another big factor in owning an additional vehicle would be the cost of insurance. I also worry about the addition of another vehicle leading to either:
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an increase in overall fuel usage - rather than a decrease - by the family due to the availability of an additional vehicle; or
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an increase in overall maintenance costs per mile due to a reduction in use of one of the vehicles that would lead to maintenance intervals based on time rather than mileage.
We seem to agree, overwhelmingly, that we don’t have enough info to make a solid recommendation at this time. There are too many unknown factors to know if buying an additional vehicle would save or cost money, and we have no reason to know without acting as fully-informed financial advisers.
Get a JC Whitney catalogue, buy everything it touts to increase mpg, you’ll get a thousand miles per gallon - at least that’s what I calculated 50 years ago.
Do you have a tachometer on your dashboard? If so, use it to adjust your speed in top gear. Once you get into overdrive, run at the low end one the tachometer, but don’t go so slow that the engine lugs.
All good suggestions. A couple more from an Avalanche owner - i.e. a Suburban with a box. Proper alignment is key but the toe-in should be set to be as close to zero as the spec recommends. The least amount of toe-in or out will allow the tires to roll without scrubbing. Synthetic lube in the axles. Synthetic oil in the engine. Doesn’t do much, but it will improve mpg’s a bit.
Mentioned in a few posts, be careful how you drive. Be super smooth on the gas, use the cruise, don’t speed (its a barn door on wheels!). HOW you drive is probably the most important. The engine mod stuff is basically bupkus.
None of these things will improve things by much. Maybe 1 mpg at highway speeds at best.
Someplace buried in the EPA website is list of tested MGP saving devices.
To save you some searching…the EPA’s conclusion…unless you made extreme modifications to the engine or tranny…there wasn’t a simple solution to get better gas mileage.
I disagree, but it depends on your driving style. For some drivers (with a lead foot), a substantial improvement is possible by shifting to a very conservative driving style.
1 mpg IS a substantial improvement in a Suburban getting 15 - 16 mpg on the highway. That’s 6%. I am assuming the OP isn’t treating the gas pedal like a foot pump.
This is not a Gasoline additive! It is also NOT a Miracle additive. it is an engine friction reducer. Maybe you should “read” what I wrote! It is an Oil Additive that reduces friction within the engine. Less friction means better performance for less fuel burned. It works for Diesel Engines and has been used by Diesel truckers for years. A 10-20% improvement as I stated is not large, but 16-17 to 19-20 MPG is a 10-20% reduction in fuel purchased in a year, that saved me about $500 in the first year. Cost of the one quart Stiction Eliminator was about $60 including shipping the first year. Subsequent oil changes only require 16 ounces put in at the oil change, so $30 per oil change. My mileage has been the same after the second oil change.
I document mileage on all my cars, and track all vehicle expenses as well. As a retired Mechanical Engineer and retired SCCA Racing sports car owner/driver, “cars/trucks” are not just transportation. They are machines, that properly maintained, can give optimal performance within their design. A Suburban is no mileage champion, but a work horse.
20% savings on fuel burned in no miracle, but $500 a year is a substantial savings on the fuel line item of expense.
But I recommended he call about gasoline engine use benefits, since I haven’t used it in my VWs.They get great mileage with out it, and the 0-20W oil in the VWs already has very low friction. The 15-40W oil specified for my Suburban isn’t like any of the new generation low friction oils. I would assume the “thomashilleke” user Suburban is also of an older vintage with specified oil of 10-30W, also a older generation, but required for that engine design.
Soooooooo… is it not an additive or an additive? Make up your mind. 
Exactly HOW does it reduce friction in the engine? By filling in imperfections in the cylinder walls?
How does it do this without also filling in the designed-in “honing” scratches on the surfaces that are essential to retain a film of oil on the cylinder walls after the oil rings go by so the compression rings will have an oil film to ride on?
I was thinking the same thing, that a 1 MPG improvement from 16 to 17 MPG saves a lot more gas than a 1 MPG improvement from 32 to 33 MPG.