I have a 4-litre Ford Ranger XLT. I was stuck, and was reving it pretty hard, then the motor began to slowly rev down and lose power. The motor was cold, now it is missing pretty bad. It could be coming from the #1 cyclinder. I have changed the spark plugs and looked to see if the push rods had come loose, but they are in place and tight. I was wondering if it could possibly be an injector, head gasket or valve or something else I am missing? I just don't want to have to take it apart if I don't have to.