I've gone to O'Reilly's to have the codes read on an Audi TT. Would think they could read the basic stuff on a Box.

Also, you could have a MAF or O2 sensor that's not quite bad enough to throw a CEL but is jacking up your air / fuel mixture. Does your engine idle smooth? Is there any black soot on your exhaust tips?

You might also try disconnecting the battery for a couple of days. When reconnected, your computer will start back at factory settings.

We do have similar Boxs so our mileage should be comparable. I will state that my city driving rarely consists of stop and go / bumper to bumper traffic. I go to work early and avoid the rush hr stuff (what little we have compared to other cities). And my readings always come from the computer. I know it might not be 100% accurate, but it's close enough for me.

I drove the Cayman to KC this weekend. The computer said 27.6mpg at 75mph.

Husker,

Thanks for the input, I do have black soot, perhaps I can take a picture and maybe you can tell, the battery idea sounds good, but 2 days really?! I actually ran into my Porsche mechanic today, and he says the car is still in break in period ~3200 and when reaching 5k+ it will get better?? I know its not about the mpg with this car, but I just want to make sure the car is running properly, and the better mpg won't hurt.

I hope everyone is OK.

Your mechanic may be a bit confused (esp after running into him). Page 12 of the owners manual says break-in is 2K mi. He may be thinking about the oil. Porsche recommends changing the oil at 5K if you're still running the original oil. Hopefully you're not since it will be quite a few yrs old.

gas mileage gets worse the closer it gets to $4 per gallon. This is a well known fact. don't bother looking it up. everyone knows already.


I have well-maintained 3.2 and have never attained anything better than 22mpg on 20 lb. factory Carrera 18" wheels.
With heavy winter wheels and tires (probably 30 lbs.) I'm down around 17-18 mpg, all highway. Yep those 10-13 lbs of rotating weight make a difference.
However I do have Fabspeed headers and exhaust.

EPA rated MPG is 18/26. 15-16 mpg is very believable in a nearly new car when shifting at >4K rpm.

My advice:

1. Give the car 5K more miles to break in and then re-check both city and highway mileage.
2. Go super easy on the throttle if you want to maximize mileage