Clogged fuel injectors are almost inevitable in high mileage vehicles. Unclogging your fuel injectors can provide one of the best ways to improve your gas mileage. Usually over time the metal screen filter inside fuel injectors becomes clogged with particulates. This causes some of your fuel injectors to flow less gas than others. This imbalance of proper fuel flow causes your vehicles computer to attempt to adjust by adding additional fuel into the system lowering your fuel economy. It is very important to have your fuel injectors serviced to remove the obstructions and restore your normal fuel economy.
1. If your vehicle is a high mileage vehicle your fuel injectors will most likely be clogged to a certain extent. A flow difference of a few % from injector to injector can make a noticeable difference in rough idle and gas mileage.
2. If you think your injectors might be clogged, have them cleaned by a fuel injector service center. There are many places on the internet that perform this function when you mail your injectors to them for around $100. Typically they will ultrasonically clean your injectors and back flush them to get all the particles out. They then replace all the o-rings as well. Having cracked or improperly sealed o-rings can cause vacuum leaks into your motor also ruining your fuel economy.
3. Do not waste your money on fuel injector cleaning solutions found at gas stations and automotive stores. Most will not be able to unclog your injectors. The best and only method you can be sure of will be the ultrasonic fuel injector cleaning service. This is because they usually provide the test results before and after the service showing the improvements that were made.
During the period I was fixing all the vacuum leaks in my motor I also removed the fuel injectors and had them sent out for cleaning service for a little over $100. There were 6 injectors in total. Some of the injectors had a flow difference of 5% compared to others. All were restored to normal flow after they were cleaned. The difference was astounding as my car used to have a rough idle. After I installed the new injectors the vehicle idled so smooth I sometimes thought it had stalled on me! I do not know how much of an increase in fuel economy I directly received from this modification as it was done together with fixing the vacuum leaks in my motor. But the combined increase from both modifications was 7 miles per gallon gain from 17 to 24 mpg. This is a total gain of 41% in fuel economy from fixing all the vacuum leaks in my motor, servicing the fuel injectors, and replacing the EGR valve!