It means a cylinder 4 misfire. Check spark plugs, spark plus wires, possibly head gasket.
Trouble code P0304 means:Cylinder 4 misfire detected
Trouble code P0304 means: Cylinder 4 Misfire Detected
Trouble code P0304 means:Cylinder 4 misfire detected
Trouble code P0304 means:Cylinder 4 misfire detected
Trouble code P0304 means:Cylinder 4 misfire detected
Trouble code P0304 means:Cylinder 4 misfire detected
Trouble code P0304 means:Cylinder 4 misfire detected
Trouble code P0304 means:Cylinder 4 misfire detected
Trouble code P0303 means:Cylinder 3 misfire detected Trouble code P0304 means:Cylinder 4 misfire detected
Trouble code P0304 means: Cylinder 4 Misfire Detected
Trouble code P0304 means:Cylinder 4 misfire detected
Trouble code P0304 means: Cylinder 4 Misfire Detected