11.6 average mpg- average speed 12.0

The other day after mostly city driving and no roads above 45, approximately driving a little over 100 miles over the course of several days, the onboard computer states I was averaging 11.6 mpg and the average speed was 12 even. Is this common for the 3.8 impala?

I have other posts listed in the impala forum regarding gas mileage. Considering all plugs\wires\filters were replaced under 1000 miles ago at most, I am starting to think there may be a problem.

Any ideas are appreciated-

Tim

my god.... do you jam the pedal down and make sudden stops instead of gradual ones? if you're doing that ur mileage will be lower per gallon

With average speed of 12 I would guess you did a lot of stopping. The hardest part of gas mileage is getting the car weight moving. A 3.8 should be getting 22-24 average around town with most roads at 35-45 mph and not too many red lights. If you are in a down town area where there is a light on every block, 11.6 might not be out of line. However I might still check if any of the fuel injectors are clogged. My daughter's 3.8 clogged when she didn't use quality gas. Since using Shell and Chevron she hasn't had any problems. But before she used whatever was cheapest.

I'd also do a MANUAL calculation of your mileage. The on board computer can be inaccurate in several situations.

Take a mileage reading while car does not have a full tank.
Fill car full.
Drive.
When you get gas again - fill it again, take mileage reading and how many gallons you got.
Subtract second mileage from first to see how many miles you went.
Divide those miles by the number of gallons you purchased with the second fill up for the actual mileage.