The compression stated below is probably better than 80% of the
vanagon engines out there.

If you are getting 140/150 no need to complain.  You are lucky!

Something else is wrong if power is poor and mileage isn't what it
used to be...

>I performed a compression test today on the engine and found 140 for
>cylinders 1 and 4, and 155 for cylinders 2 and 3. This does not look
>too good, but should that be enough to cause a low power and poor
>gas mileage (15.3 mpg on highway). I added a little oil for 1 and 4
>cylinder and test again, both compression went up to 150. I know
>this is not good but how bad is it?