Check engine light on . will not pass DEQ code po 304

Hoopers51, Code 304 is for a misfire detected on cylinder #4. Check the wire and the spark plug for that cylinder. Make sure that there is no corrosion in the boots of the wire and see if the spark plug is fouled up, or wet with gas. If the plug is fouled (a normal firing plug will have a grayish color to it) clean it and replace it. If the wire is bad then replace it. Make sure that there is no corrosion on the coil terminal when you pull the wire off. You might want to test the coil if you have an inline spark tester. These can be purchased very cheaply at any auto part store. Also what you can try is to remove the plug on the #4 injector when the engine is running. DO NOT try this with the spark plug wire. (Do this when the engine is off) When you disconnect the injector you will hear a misfire if it is working properly and this will tell you that the injector is not the problem. If there is no change then you should check for power to the injector. (once again, when the engine is running) The injector on that cylinder may be weak and is leaking. This will dump too much fuel into that cylinder causing the misfire and you will have a wet spark plug. All of these, a bad wire, a bad spark plug, a leaky injector or one with no power, or a bad coil will cause a misfire and will increase the HC's on an emission test. Good luck with this.

P0304 is a cylinder 4 misfire. depending on the model there are numerous possibilities and common issues