GreenHybrid - Hybrid Cars - View Single Post - okay... something is SERIOUSLY wrong with my MPG

lloyd123 · #5 (**permalink**) 11-01-2007, 05:05 PM

Quote:

Originally Posted by nash

Low tire pressure(s)? Check them, they should be around 35psi, 32psi minimum. I run my TCH tires at 40psi. Driving from San Diego to Phoenix Arizona and back I got 40mpg with the AC going - it was about 100F that weekend.

Unlikely but possible is a dirty air filter. I assume your speed was about the same as when you got 36mpg.

Consumer Reports says tire pressure and a dirty air filter have little effect on gas mileage:

http://autos.msn.com/advice/CRArt.as...tentid=4024120

IMPORTANT DRIVING TIPS THAT HAVE LITTLE EFFECT ON FUEL ECONOMY

Keep tires inflated. Our tests show that driving on moderately underinflated tires is more of a safety concern than a fuel-economy issue. We set the pressure in all four tires to 10 psi below that recommended by the automaker. This reduced highway fuel economy slightly, by about 1 mpg for the Camry and by a much smaller margin for the Mountaineer. But more importantly, underinflated tires provide much less grip for turning and stopping and run much hotter. Overheated tires wear faster and can lead to a blowout. Check the pressure of your vehicle's tires at least once a month, when the tires are cold. Also check the tires before and after long road trips. The recommended tire pressure is found on a label inside the car—usually in a doorjamb, inside the glove-box lid, or inside the fuel-filler lid.

Keep your air filter clean. According to our tests, driving with a dirty air filter in modern engines doesn't have a significant impact on fuel economy, as it did with older engines. While fuel economy didn't change, however, power output did. Both cars accelerated much more slowly with a dirty air cleaner. We drove both vehicles with their air cleaners restricted and found little difference in gas mileage with either engine. That's because modern engines use computers to precisely control the air/fuel ratio, depending on the amount of air coming in through the filter. Reducing airflow, therefore, caused the engines to automatically reduce the amount of fuel being use

I agree that if the "check engine" light isn't on that it's probably not the engine/fuel injection causing the problem. Could it be something like the emergency brake not fully releasing or an alignment problem?