Re: 2003 civic EX Engine sputtering in idle with Check Engine Light
They have to be getting spark since he can start the car. It sounds like ignition though. I would check the cap and rotor for any severe wear or cracks. Also test the igniter as well since it's possible that it is not giving off enough spark per cylinder.
Also the timing may be bad and the spark is coming so late the engine is reading it as a misfire. If any work was done to it right before it happened or if you were in an accident, I would check everything that was touched. If you can remember what happened right before the CEL came on, that'd be a lot more helpful