2004 Dodge neon 2.2 engine while running at idle, even in neutral or under load, about every 30 seconds to a minute, the engine stumbles, but the rpms on the tach do not show any change, steady 1500 rpm

My first thoughts were 1.) bad mass air senor (this car has a plastic caped mass air, thus no wire to clean 2.) coil, as this car still has one coil pack and the problem surfaces as the car heats up as is erratic, similar to the old oil filled coils overheating. 3.) timming belt, but his would not be eratic 4.) gas filter, which apparently is in the gas tank as a sealed unit with the gas pump... if it is this, this car is getting a high flow pump with an inline filter, so filter can be changed yearly... I am still thinking, as ideas or experience with this car, please feel free. Thank you

correction, 2.0 engine, a typo. Thank you