Actually your mileage will fluctuate while the engine is still breaking in. Last week I got 311 mi on one tank ... This week I am at 260 miles ... Could be my varying driving style and occasional road rage slamming the gas pedal ... but I don't think so ... Engine break-in will continue well into 10,000 - 25,000 miles mark on the odometer. And, at that time you should be able to guage with regularity what your mileage is and will be. Another issue addressed by this is that folks have mentioned switching to synthetic oils on the first oil change, but this is actually discouraged. Many mechanics will tell you to continue using regular oil well through the engine break-in period, and then switch to synthetic in that 10,000-25,000 mile period.
If you check the Mobil 1 site you will see the break-in taboo is a myth. They list several high end cars that come standard with synthetic in brand new engines from the factory.:4: The following is from their site-
You can start using Mobil 1 with SuperSyn™ in new vehicles at any time, even in brand-new vehicles. In fact, Mobil 1 with SuperSyn™ is original equipment (it is installed at the factory) in:
All Porsche vehicles
Mercedes-Benz AMG vehicles
Ford Mustang Cobra R
All Aston Martin cars
One of the myths that persists about Mobil 1 is that new engines require a break-in period with conventional oil. Current engine manufacturing technology does not require this break-in period. As indicated by the decisions of the engineers who design these high-performance cars, Mobil 1 with SuperSyn™ can be used in an engine from the day you drive the car off the showroom floor.
That being said, I'd wait until 5k or so to switch to synthetic since Honda claims they have a special oil for break-in installed.
I know that some vehicles do come with synthetics straight from the factory, but I would consider the possibility that those vehicles are manufactured with tolerances that allow for this. I've already decided that my first change will be at 5,000 miles due to the dusty conditions that I drive in regularly during trips to my mother's house most weekends, soccer fields with gravel parking lots every Wednesday and Saturday, and a right now they are building a house right next to me and our street has been a mess for 6 months. I will be using Mobil 1 5W30 synthetic.
With 2800 miles on the clock, my mileage is abysmal - 14.4 mixed - 17.3 highway cruise (Atlanta to Nashville)
This is my only serious complaint with my Pilot and I don't know what to do about it. I'm taking it in at 3000 for an initial oil change and I will bring it up then - but what...I'm sure I'll get a snicker and some corporate crapola.