[shorod]

Have they checked the wetness of the spark plug in cylinder #4 after the car's been running? If the plug is dry, there may be a fuel injector that is failing.

One thing to try would be to swap the coil, spark plug, and fuel injector to another cylinder, clear the codes, and see if the misfire follows the itmes or stays with the cylinder. Check the cylinder compression as well.

If all that checks out, you'll want to have the wiring diagrams and check for voltages to the coil primaries, fuel injector, and some of the sensors.

-Rod