Gumout fuel injector cleaner for high mileage cars...

[Tiger]

Do a test... fill up car... reset trip meter and drive until you refill... then calculate your actual mileage.

[spyrot1]

Do a test... fill up car... reset trip meter and drive until you refill... then calculate your actual mileage.

I'm usually in a lot of stop and go traffic, so my average mileage is closer to 20 to 21mpg. So a test for actual gas mileage will probably have those results (give or take 1 to 2 mpg).

That said, I'm just happy to see my highway mileage go up, even if it's only on the OBC (my assumption is that my average mpg will also go up slightly). Even if the new mpg numbers are bogus, the fact that they changed for the positive means that at least the OBC thinks that the gas mileage has increased.

The perfect test would be to get on a highway with a full tank and then measure how far you can go before you run out of gas. That would give you a true range and mpg (for highway driving).