dodge nion code issue?

There are only four things that have caused my Neon to misfire. Bad spark plugs, bad spark plug wires, oil in the spark plug holes, and leaking fuel injector o-rings. The fact that it is a twin cam isn't really relevant unless you have a timing issue or damaged valve train components, which would cause you many more problems than a simple intermittent misfire. Check out a site called Neons.org. I go there all the time. Lots of information on all different Neons. Here's what happens:

Bad spark plugs don't always fire. Or they fire weakly. Replace them with properly-gapped ORIGINAL EQUIPMENT spark plugs. Fancy high-performance ones can cause problems.

Bad spark plug wires fail to get the voltage to the plugs, either by cross-firing or by blocking current completely. Replace them with FACTORY wires. I have tried aftermarket wires, they failed.

Oil in the spark plug holes cause the spark plugs to ground out, preventing them from firing. Oil leaks into the holes through the seals in the valve cover. Pull out all the plugs, spray some carburetor cleaner in the holes, insert a rag on a stick into the holes, and mop up all the oil. Make sure you get it all.

Fuel injector o-rings dry out and crack due to exposure to heat and fuel. They allow air to suck in, or worse, they allow fuel to leak out, depending on what side of the injector they are on. It's a quick job to replace them all. Cheap, too.

All four of these cause misfires, and will trigger the check-engine light. All four are cheap fixes.