Altitude/AirDensity Will Play a Roll in the MsPG on that Drive ~ Although I Would Not

Expect it to be that Big of a Hit ~ As He Looses Alt & the AirDensity Rises the ECU will Add

More Gas' to keep the FuelMix' Stoichiometric ~ Additionally that Denser Air will cause More

AeroDynamic Drag & so More Load on the Eng' which will require MoreFuel ~ Then there is 

the OctaneFactor ~ Denser Air @ Lower Alt's allows an Eng' to Make Higher Compression 

which allows Knock to occur Much More Easily & when the ECU then makes the AntiKnock 

adjustments MsPG GoDown ~ 

        There is also some info that suggests that Gasolines in the MidWest may contain More

Ethanol than out here in the West ~

                                                        ORR ~ DeanB

> 
> On Sat, Jul 30, 2016 at 12:03 PM, Tom Stone <tstone8359@aol.com> wrote:
> 
>> My son is driving his '84 Vanagon with a newly installed 2.5 Subaru engine
>> in it back from Colorado to Ohio.  He has noticed a decrease in fuel
>> mileage as he comes east.  He says it runs great and accelerates normally
>> but he is concerned about the mileage drop, from 22 to 16mpg so far.
>> Sounds like a sensor problem but I know nothing about Subarus.  Anyone have
>> any suggestions?
>> 
>> Tom
>>