Hey guys, I'm just wondering what's going on with my Fit, I know I have bad back brakes that I'm getting fixed Tuesday, but man, my mileage just seemed to drop. I fill up my tank everyday, sometimes twice a day because I drive a lot for work both city and highway driving. I get fuel additive every week just to help but it doesn't seem to do anything past the first fuel up. I plan on getting new spark plugs sometimes next week as well. I do have this loud squealing grinding noise when accelerating still. It stopped for most of the summer but whatever it is came back recently. It's coming from under the car, but I'm not sure what or wear it is. Any suggestions on how to up my MPG?

 

When braking do you feel a pulse in slowing down that pushes you towards the steering wheel, then eases up, then forward again, ect?

I've helped folks that let their brakes go too far. Got real loud, then some months later got quieter. They actually wore right through the metal backing plate on one of the shoes and were grinding down a piston in the brake caliper. What came next was the piston extending too far and brake fluid seeping out around it, leaving 'em to rely on the parking brake to avoid an accident while bringing their kids home from school.

but anyways.. If you're experiencing pulsing while braking, the brake pads may also rub while you're accelerating, creating rolling resistance that reduces efficiency and thusly, fuel economy.

Another consideration in way of rolling resistance (carrying the assumption that you have no check engine light or odd noises from the engine bay) is wheel alignment. Hitting potholes n curbs can throw it off as yuh know, and leave the wheels pigeon toed or.. the opposite of pigeon toed. when it's gone on for a while, this can be identified by irregular tire wear like "tire cupping". can get a free or likely very cheap inspection at corporate chain alignment shops.. Only the front wheels get aligned. don't let em tell yuh different.

If you think it's neither of those I'd need more symptoms.

 

Possibly a back brake dragging?? That would definitely affect your mpg.

 

In addition to the above, clean off MAF sensor (there is a special spray from CFC that I use. Consider an upstream oxygen sensor if the MAF cleaning doesn't help.

I need to pull the rear drums myself and see what shape they are in.

 

I noticed a reduction in fuel economy when I switched tires. I have Yokohama Avid Ascends, love the superb traction in all weather conditions. However, I used to consistently average 31-32 mpg combined driving, and only get 28.5 now. This is my second set of these tires after the factory Dunlops wore out around 40k. Disappointing to see the mpg drop, but in the end I favor the Tire performance over the gas mileage given the NY and CT winter weather.