Hi ..
you could say what trans you have.
I would say a manual trans 1.9  Waterboxer Westy will do about 20.5 mpg
tops.

also ..higher temps are better for fuel mileage...coolant running temp,
and ambient.

I hauled a friend, camping stuff, and a transmission in late August over
the cascade mountaings..
85 Westy, manual trans, 1.9 wbxr .

I had to climb one hill at 35 mph in 2nd for about 5 miles ..hated doing
that ...just wouldn't pull 3rd.
'normal cars' go up that same grade about 45 to 50 mph .
Then driving on a fast two lane highway I drove another 140 miles or so
to my destination .
and calculations said 20.5 or 21 mph ...
I was quite impressed, and I passed a few trucks going downhill at 80mph
once or twice..
I'm real pleased anytime a gas vanagon with manual trans does 20mpg at
60 to 65ish mph.

Poor fuel milage can be one of the very trickiest things to fix.
If you find something ...or the tech does ...great..
often it can be illusive though.
Your oxygen sensor is working ?
no restricted cat or muffler ?
I just had a cat that looked nice on both ends..
but it made the van run all farty sounding at idle..
it was failing inside, not visible from either end.
that can't be good for fuel mileage.

scott
turbovans

On 5/2/2012 10:00 AM, B Feddish wrote:
> So on my trip north this past weekend I only got 17 mpg on the highway with my 83.5 w/c Westy. That is my normal city mileage.  I should have gotten at least 20 if not 21-22.  All the usual suspects have been checked.  if anyone has any last minute suggestions for me that I can try this weekend let me know.  Otherwise it looks as though I will have to take it the expensive mechanic who I know is going to charge at least a few hours and still may not find something.
>
> Thanks,
> Bryan
>