My 2021 Hybrid started doing a little worse as it got further away from the last service - probably down to about 42mpg or so. I let it go too far between service intervals. The next time I took it in and got the oil changed, it got better immediately. I've been getting around 50 mpg since.

Maybe they spread the recommended oil changes out too far considering they're not using full synthetic. I have a leased car that includes service, but you only get a certain amount of free service visits, and they won't last the length of the lease, even though I drive under 12K miles a year.

Maybe check your tire pressure and change the oil if it's anywhere near time.

 

My 2021 Hybrid started doing a little worse as it got further away from the last service - probably down to about 42mpg or so. I let it go too far between service intervals. The next time I took it in and got the oil changed, it got better immediately. I've been getting around 50 mpg since.

Maybe they spread the recommended oil changes out too far considering they're not using full synthetic. I have a leased car that includes service, but you only get a certain amount of free service visits, and they won't last the length of the lease, even though I drive under 12K miles a year.

Maybe check your tire pressure and change the oil if it's anywhere near time.

I would die for 40 mpg, even once!!! My 2022 has one time only gotten 36mpg, early on at about 4K. Now, I'm lucky to get 30 on a good day.

 

I'm not sure where you live, but all hybrid and electric vehicles get reduced mileage in colder weather. The batteries have a temperature sweet spot, and efficiency degrades at other temps. When I had an Accord Hybrid (in New England), I got about 50mpg on my commute in the summer and closer to 30mpg in peak winter.
Also, not sure how you're judging the performance of the solar panel, but the output of that solar panel is small compared to the needs of the car battery. Even if it stops working completely, the impact on your mileage would be minor.

 

It’s amazing how much the weather affects the mileage:

Low to mid 50s in the summer and mostly low 40s in the winter.

The solar panels don’t do a whole lot. Technically they should be more efficient charging in cold weather, but the winter sun is at a low angle which negates it.

I’m hyper careful about my speed to try and max out my mileage; my route to work is 55 mph a good part of the way. Going 70 on the interstate tanks my mileage by 5 mpg or more.

 

Too many variables. Weather. Driving habits. Route. Oil used (some dealers use a slightly higher weight oil, which will reduce MPG, manual says it's ok). It seems this car see its peak efficiency in spring/summer months (50F-90F) and highway/long stretches of driving with speeds between 45mph and 65mph. Anything over 65mph, the MPG goes down.

 

2022 sonata hybrid blue currently at the dealership diagnosing hard shift occasional slip torque converter, feels like it does not disengage. The tires are ruined from what feels like the vehicle is dragging, the vehicle slows dramatically after relieving the gas pedal, going downhill at any speed and any grade the gas mileage has never been power and the engine doesn’t seem to charge the batteries at all. I hear a water trickling noise on the driver side for every time the engine engages, a wobbling sensation from the floorboard within EV mode under light throttle depression almost like a bad driveshaft, but the vehicle does not come equipped with one as you come to a stop the vehicle feels like it stops in second gear, then shifts down after the vehicle has come to a stop have you experienced any of these problems?

 

Update:
1) So far Hyundai US is nearly useless. Still on the "no-code, don't know."
2) I have to take the car to another dealership and see if they can find anything. It still won't have a code, but I have a case number now to give them.
3) Since the oil change, for my 15K service, I am "up to" 43mpg. I'm going to put at least half a tank of mileage before I take it to the other dealer. I want the computer to have enough miles so they can't call it an anomaly.

 

Problem is that this mileage slump started in August. Last winter I maybe lost 2 mpg, not 10.
I just waited, to bring it to the dealership, till now because that is when I was due for maintenance.

 

1.

I've had the car for 2 years. It only has 14K miles. I drive about 500 miles a month. Runs fine, but......



Starting in the summer, the solar panel didn't seam to be charging the battery as well as before.

The mpg slipped to mid 40's.



Then in September the mileage went down to 40 mpg. Has been the same for 3 or 4 tank fulls now.



Just took it to the dealership and they say there are no codes, so there is nothing they can do.



I did call the US consumer number and started a ticket with Hyundai.



Anyone have this problem before?



Thanks

Martin

1. Get some really good injectors or carb cleaner. Put in your fuel tank, full container full gas tank. Drive. 2. Use FULL synthetic oil like Amsoil, Mobil one 0-16 weight. Drive. 3. Do not use jack rabbit starts or hard braking. 4. Drive speed limit or slightly less. When passing be gentle on gas pedal. 5. Use Lowest fuel grade. That is what the gas engine is designed for. And assuming you are talking about hybrids. For non hybrids, most of the same applies. As for fuel grade, always follow recommended grade. I have 21 sonata hybrid. I routinely get over 50. Sometimes going with the wind, up to 59. But into the wind as low as 45.

 

Yeah, I think that this is probably something on your end. As is the case for everyone else, my mileage dropped in winter (39.4 was my worst tank), but is returning to normal (~49mpg over 30 self-calculated tanks) now that the weather's improving. Until you start seeing your mileage drop into the 20s or teens--and more importantly, your car starts to FEEL and drive differently somehow--there's probably not much Hyundai can do. Drive more conservatively, watch the energy monitor, etc.