Seven Car Problems That Lead to Drops in Gas Mileage

Improving fuel economy is very important to most drivers. Driver-actions, such as idling, jackrabbit starts and carrying extra weight in the car, are often the culprit for ongoing poor gas mileage. However, a sudden change in fuel efficiency absent any obvious driver behaviors can indicate a more serious problem. Keep vehicles in peak operating condition and maximize miles per gallon all the time.

1. A noticeable drop in fuel economy after an oil change can indicate the car received the wrong oil during the change. Poor performance, temperature extremes and a drop in mpg indicate an incorrect oil viscosity. Oils that reduce engine friction, either synthetics or the oil recommended in the Owner’s Manual, may resolve the problem.

2. Improperly inflated tires can cut gas mileage by over three percent because the friction between the tire and the road is out of proportion. Pounds per square inch (PSI) are listed on the side of the tire. This represents the maximum inflation for the tire, but not necessarily the right pressure for road conditions and temperature. Check tires frequently and keep them at the manufacturer’s recommended pressure for conditions.

3. Newer cars have computer-run thermostats that regulate engine coolant. If this thermostat is broken or defective, the vehicle cools itself all the time even if cooling is not needed. The result is bad gas mileage and poor vehicle performance. Have a mechanic run diagnostic tests and replace the thermostat if it is malfunctioning.

4. Older vehicles that use carburetors may suffer from clogged or dirty air filters. This results in a gas mixture that is too rich due to poor air intake. The car uses more fuel, which not only lowers gas mileage but also harms the engine. In vehicles without carburetors, blocked air filters cause poor acceleration but not mileage decreases.

5. Malfunctioning oxygen sensors also help regulate the mixture of air and gas in the engine. This can affect gas mileage by 20 percent or more. Have air filters cleaned and unclogged, and replace oxygen sensors if needed to improve engine performance and efficiency.

6. Misfiring spark plugs, corroded spark plug wires and bad spark plugs contribute to poor mileage statistics. They work together to ignite combustion in the engine, so a problem with any of these areas causes the engine to work hard to maintain operations.

7. Fuel injectors are the mechanism for getting gas into the engine. If the injectors have gone bad or have a leak, less fuel enters the engine. This makes vehicles with malfunctioning fuel injectors run less efficiently.

Auto Novice

Auto Novices is a blog, that was set up in November 2011, which tries to help inform new & old automobile owners about various subjects from keeping their car in good working order right through to tips on buying a new & used motorbikes. GUEST POSTS: If you would like to produce a guest post for this blog then please contact us via the link in the navigation menu at the top of the page.