I’d love some help. Over the last year, my 2012 Toyota Highlander Limited (95k miles) MPG has rapidly diminished MPG. We drive mostly in the city, running errands and picking up kids with occasional trips up to the mountains for skiing and 2x/year 1,000 mile roadtrips. About 10k miles per year on average.
The vehicle is rated 20/25 mpg city/highway. Since we are mostly city driving, we experienced ~18-19/mpg. Over the last year, mileage has been diminishing to the point that it is ~12 mpg (40% lower than rated!). I took the vehicle to our local repair shop in early October, and they did the following:
Replaced spark plugs
Fuel induction service
Replaced air filters (engine and cabin)
Alignment
Nothing has changed! Mileage is still at about 12mpg. Any thoughts on what might be happening, and what I can do about it? Thanks!
Make: Toyota
Model: Highlander Limited AWD
Year: 2012
Mileage: 95k, give or take
Give some ideas about the maintenance history. Have you followed the Toyota rec’s from the owners manual?
How do you check on your MPGs? The only sure way is to track mileage and gallons over a good long time (at least a few full tanks) and do the math. If you’re just looking at what the computer says, that’s usually pretty reliable, but you want to check up on it.
Is/has the check engine light been on? If so, then the shop would have read the codes and they should be on your receipt.
With or without a check engine light, like @George_San_Jose1 implies - someone needs to put a scantool on it and check things like coolant temp readings, O2 sensor behavior, air temp readings, and look at fuel trims.
So some idea of what the shop did and said beyond just replacing parts would be nice.