Mastering the P0304 Code Diagnosis Expert Insights

Check the wires and the pigtail that goes to the coil pack. I've seen this happen from a wire cracking close to the pigtail (not noticeable ... If that doesn't yeild any results, check for an intake manifold gasket leak. You can do this with a boost leak check or spray some brake clean ... That code has two possibilities: 1. Spark: Bad coil, bad spark plug, poor primary connection to coil, primary wiring issue 2. Inadequate fuel: Fuel filter, ... Compression test is a must at this minute. If compression is low, check valves. If compression is ok- injector, coil, spark plug, wiring is to blame. A friendly local garage pulled codes, P0302 and P0304, cylinder misfires. We erased. Switched plug wires around to assess. Ran for check engine light, and ... yes, its actually what i was thinking, its failing under heat. Typically you're right the whole coil fails but i've seen weirder things happen. P0304 = Cylinder #4 Misfire Detected. Sounds like it maybe an ignition problem, if you are taking it to the mechanic, tell him its Cylinder #4 that is ... P0304 is for cylinder 4 misfire. That would be my next step. You don't have to change all the ignition coils out. Just the one for cylinder 4. Still getting the error on 4. Anybody have any luck with this code? 2007 Jeep Compass 2.4L FWD 140K miles. The engine runs very rough and the P0304 Cylinder 4 misfile MIL code comes up. When the car cools down again, the engine runs smooth.