Scotty, thanks for all your helpful videos and information. In Jan. 2018 I purchased a 2015 Nissan Altima SL 2.5 liter 4-cylinder (built in October 2014). At that time the car had 35,000 miles. It now has 132,000 miles. Brand new, the mpg was 32. Nowadays, it hovers around 25 mpg. When I do more highway driveway, it increases a bit. A few days ago, I had the spark plugs and valve gasket cover replaced. A week ago, I put the fuel injector cleaner that you recommended (from your buddy in Albuquerque) in the car. Is there anything I should do to continue get the car closer to its original mpg? I just saw your video about another product from your New Mexico buddy that you placed directly in an engine. Should I use that and/or something else? Also, should I do a transmission flush? I have never had the transmission flushed or fluids changed. I topped it off a few weeks ago with transmission fluid that I purchased at a Nissan dealership. Lastly, Midas mentioned low engine coolant. Does it matter if I have that company replace it compared to a Nissan dealership in terms of the quality of the product that will be used? I plan to keep this car for another 2-3 years, so I want to keep it operating as efficiently as possible.
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It now has 132,000 miles. Brand new, the mpg was 32. Nowadays, it hovers around 25 mpg. When I do more highway driveway, it increases a bit.
How fast are you going on the highway? 3 years ago, when gas was over $5 a gallon, I managed to beat the EPA's estimate for highway MPG in my 1999 Ranger and it has 300k miles on it. That's over twice the mileage as yours. It was EPA-estimated to get 19 MPG highway, I managed to get almost 22.5 MPG one time. I was driving mainly on the highway, putting 275 miles a week on the truck. I got really good at coasting instead of stepping on the brakes- that wastes kinetic energy that would otherwise be useful to coast. When you coast, you're using the kinetic energy that's already in the car.
Every time you double your engine's RPMs, you're consuming 4x the fuel. Stop and go traffic on the highway also reduces gas mileage.
Is there anything I should do to continue get the car closer to its original mpg?
Check your air filter.
Also, should I do a transmission flush?
Never flush a CVT or automatic transmission. Debris can get into the valve body if it's a conventional automatic and then the only option will be to either replace the transmission with a new one, or taking it to a transmission shop to be rebuilt. Jatco has crap CVTs a front-wheel-drive automatic transmissions.
I topped it off a few weeks ago with transmission fluid that I purchased at a Nissan dealership
Is your transmission leaking? You shouldn't need to do that.
Midas mentioned low engine coolant.
Never, ever go to chain shops, especially Midas and the like. They love to upsell. When the car has sat overnight, take off the radiator cap and look inside. It should be pretty close to the top of the radiator. If it's not, top it off and replace the radiator cap. If you have no record of it being changed, it's a simple procedure: https://youtu.be/mxm3E5SkHrI?si=mYULbwggEZ0Flvu- You can easily do it yourself if you have a few hours and basic hand tools.
@justin-shepherd I don’t drive fast compared to many drivers. In fact, some folks in my circle prefer to drive if we are going somewhere together. I definitely am not heavy on the accelerator. (I’ve heard stories about some Altima drivers.)
Normally, transmission flush is not recommended, especially at this milage. Just do drain and fill. Stick with OEM fluids. You can try to clean MAF sensor if it has one, keep air filter clean and tires properly inflated and that's about all I can think of to improve mpgs. If none of the injectors are clogged and all sensors work properly, there is not much else that you can do except not be heavy on gas pedal and not carrying to much weight in the trunk.. Don't fall for "fuel saving" scams..
