Well problems with injectors usually starts with misfiring, or having a hard start or hesitation. Listen for sounds but if there are other sounds it might not only be the injector. Check for engine crank. You said that there are leakage, it could be a dangerous thing because fuel leaks from your injector can cause a burn in your vehicle's engine. If there are leakage it must be replaced immediately.You could try visiting autopartswarehouse.com (lots of new carparts here) for replacement. Just note that before you test the equipment-- fuel injection system, you must relieve the fuel pressure by having the vacuum hose disconnected from the fuel pressure regulator and remove the fuel tank cap. Hope this helps. Thanks!