The causes of bad gas mileage in a car or truck can be caused by many reasons, some very simple to fix and others more complex. If you suspect that you have a car problem that is causing your bad gas mileage it would be advisable to check the easy things yourself first before you take the car to a professional. For car problem diagnosis help we usually enlist the help of ATS. ATS has access to a library of information on all makes and models to help the "backyard" mechanic diagnose car trouble.
Car troubleshooting has to be done in an orderly fashion. First you have to decide and determine what part of the car your problem is in, such as, fuel supply problems, electrical problems, or electronic control module problems. If you have a car problem that has set a trouble code once you determine what the code means it should help you narrow down the particular area of your car where the problem is and whether it would cause bad gas mileage or not.
As I mentioned before about using ATS for help, it can save you time and money and keep you focused on fixing the problem you actually have. Car parts are expensive so you don't just want to throw money at your problem making it more expensive to fix than necessary.
What Causes Bad Gas Mileage:
1) A bad air cleaner will restrict air flow into your engine and cause the engine to run inefficiently and burn more gas than necessary.
2) Faulty fuel injectors - if the injectors stay open longer than required more fuel will be injected into your engine than necessary.
3) Low tire pressure - under inflated tires have a higher rolling resistance that correctly filled tires
4) Engine not reaching operating temperature making the EEC system "think" the engine needs to run on a rich mixture to warm-up. ( Possible thermostat problem could cause this).
5) Bad gas - if you use cheap gas try using a better grade of gas before you do anything else. Just changing the fuel is a cheap fix.
6) Accelerating too fast - You can be accelerating too fast and not even realize it. To find out if you are accelerating too fast a vacuum gauge will tell you as it shows a vacuum drop under acceleration. A good multi-task tool is the Scangauge II that provides an electronic display of vacuum readings and other engine performance readings as you drive.
