Dodge Neon Wiring

I'm Working On My Sisters 2000 Dodge Neon I Finely Got It Running. However I Do Have A Misfire On My 4 Injector. I Forgot The Code It Gave...

My Neon Has A Sohc 4 Cyl Engine And I Want To Put In A Dohc Engine Do I Have To Change The Engine Wire Harness That Connects To The Computer...

I Have Replaced The Fuel Pump, Fuel Filter,and Pigtail Connector Which Goes To The Fuel Pump. Before Doing These Things,i Will Shed A Little...