P0303 code for 1998 Ford Taurus with 3.0L engine.

Question:

My check engine light keeps coming on and got a code P0303 misfiring code on cylinder #3. I checked the compression on this cylinder and it is comparable with the rest. I have no vacuum leak and got 18 inch when I measured it. I swapped the injectors from #3 to #1 cylinder and after a week, the code still returned for #3. Finally, this code is also intermittent and I am about to bring it to the dealer if you have any suggestion.

ATS Adviser:

Going by ATS database, one fix that you might have missed is the ignition coil pack. Have you tried switching the plug wires too? If the coil pack is borderline defective, it will run OK and might test well if you measure it with a voltmeter. However, if it is used for a few days especially under load, it might start to falter and show you the code. That would be the test I would do if I were you before going to the dealer.

ATS Tip:

You can also use an electric air heater and apply it to the coil and see if the part will fail.