My 2014 Accord EX L suddenly had its MPG go from about 30 to about 26 - Dealer did a injector cleaning etc - no problems were found - problem still exists - Does anyone suspect or have a CVT transmission that caused gas mileage to plummet? Car has 66000 miles.
Winter blend gas and winter driving will drop gas mileage. Has anyone checked the egr valve?
If the OP lives in a region where winter temperatures plummet, that is the likely cause of the problem, as ALL gasoline engines will yield lower MPGs in winter weather. That being said, I really hope that the OP isn’t warming-up the engine for more than… maybe… 30 seconds before driving. Extended warm-ups are not necessary and will only lead to an even greater drop in gas mileage than simply driving in winter weather would produce.
I have a 2017 Accord EX-L with the same drive train as yours. With summer blend gas, I get about 38 mpg on the highway with no traffic jams. With winter gas, I get about 34. Off the highway, I get less than 30 mpg with winter gas. If you live in an area that gives cold enough, you are seeing the effects of winter gas.
Also tire inflation plays a small role in MPG. Lower temps = lower tire pressure = more rolling resistance. It’s especially noticeable here where there are days in the 80s and 90s F and also nights where it is in the teens or more below zero F.
Your 2017 car has a TPMS but I am not sure if that would activate if all the tires drop approximately equally.
When the ambient temp in my area dropped into the low 20s last week, I checked my tire pressure, and–sure enough–it had dropped by 4 psi, all around. So despite the fact that I had done my regular tire pressure check only a few weeks previously, I had to pull out my tire inflator and inflate my tires back to their “normal” level.
When was the last time that the OP got up close and personal with his tires, and checked their pressure with a hand-held gauge?
Agree, normal drop in cold weather. Just make sure your tires are inflated to the sticker psi when cold.