Subaru fuel milage. Improve?

Question

new timing belt and water pump. Mobil 1 synthetic oil, new air filter and new Bosch +2 spark plugs. Only 23 mpg on highway. Any ideas? Oh, it's a '99 Impreza outback 2.2 109,000 miles

Answer 1

The biggest thing that we are finding on about 65 percent of the vehicles since this gas (BS) is that the vehicles alignment is out of specs and in some cases it is only out 1/16th but it is enough to effect the gas mileage.