2005 Dodge Neon running rough

Hello all - brand new here. Anyway, my 2005 Neon (60,000 miles) is running rough at random intervals whether at idle or going uphills mostly.

The "check engine" light is not on BTW.

Two weeks ago my "check engine" light came on and I changed my spark plugs, which solved the problem, for about a week.

So what could it be...air filter, fuel lines, etc? I'm not a mechanical expert by any means. But since the CE light isn't on, I will assume it's not an electronic problem.

Thanks in advance for any suggestions or a diagnosis.