At what mileage did you get your valve adjustment?
In the recommended maintenance schedule in the owner's manual, Acura recommends a valve adjustment every 105K miles, regardless of time.
The recommended maintenance schedule in the owner's manual should be your guide to what to do and when. However, if you're concerned about your gas mileage, you may want to do the services that have the biggest effect on mileage more often than recommended. Those would be the air filter and valve adjustment, and maybe the spark plugs. And, as I mentioned, cleaning the EGR valve and ports, which isn't in the schedule.
So maybe you might not want to wait until 105K miles to have the valves adjusted, if you want to see if it improves mileage. Again, though, I seriously wonder whether you're going to suddenly get 18 mpg, since that's unusually high for mixed local and highway driving, in my experience, but you can give it a shot if you want.
As for the recommended intervals in the manual, some of the items need servicing based on mileage, others based on time, still others based on a combination of mileage or time, whichever comes first. Here are the recommended intervals for the most significant service items, according to the owner's manual:
- change oil and filter - every 7500 miles or 1 year, whichever comes first
- brake fluid - every 3 years regardless of mileage
- transmission fluid and transfer case fluid - first time at 45K miles or 3 years; after that, every 30K miles or 2 years, whichever comes first
- VTM service including differential fluid - first two times every 15K miles or 1 year; after that, every 30K miles or 2 years, whichever comes first
- coolant - the recommendation is 120K miles or 10 years, whichever comes first, the first time, and after that 60K miles or 5 years, whichever comes first. However this will be flushed (replaced) when they replace the water pump, and that will re-set your interval for changing the coolant
- air filter - every 30K miles regardless of time
- cabin dust and pollen filter - every 30K miles or 2 years, whichever comes first
- adjust valves - every 105K miles regardless of time
- spark plugs - every 105K miles or 7 years, whichever comes first
- timing belt (usually also includes water pump) - every 105K miles or 7 years, whichever comes first