Your Hyundai fuel injectors are vital to the healthy combustion cycle of your engine, so don't stint when it comes to replacing these delicate instruments! When you start to notice problems with your combustion system, take the time to diagnose if the problem lies with your injectors, or other components like the sensors. The common symptoms of injection problems are engine detonations or misfires, knocking, loss of power and a drop in your gas mileage. Detonations will eventually jar your engine so badly that damage might occur there. When it is time for an emissions test, you might fail because of the high levels of hydrocarbon and carbon monoxide emissions that come as a result of unburned fuel passing straight to your exhaust system. Your Hyundai fuel injectors will often start to fail because of shorted or open circuits leading to the sensors and the on-board computer that regulates the engine functions sometimes short, or develop shorted turns, or an open circuit. In either case, the injector will need to be replaced. Do you have an ohm meter? You can use it to measure the coil resistance of the injectors. The resistance of the coils should probably be within about plus or minus 10% of each other. Another test to try on your Hyundai fuel injectors: flow testing, which compares the actual flow rate of each injector to factory specifications. If these tests pinpoint the issue in your combustion system comes from the injectors, order your new Hyundai fuel injectors here and replace them yourself.