I have a 2001 Dodge Neon, 2.0l. Check engine light with a cylinder 1 misfire and cylinder 1 injector error code. I replaced the #1 injector, spark plugs,spark plug wires, and ignition coil. She is running slightly better, but still misfires frequently (ie every time i run her), particularly at idle and low throttle. Fuel pressure at the injector rail is a bit low - 49 - 50 psi. Is fuel pressure ~4 psi below manufacturer specs enough to suggest a fuel filter/pressure regulator replacement?

 

Did you clean all 4 injectors? It looks like you covered everything....