I'v pulled the same code just a week after replacing my camshaft position sensor with a brand new one from FORD. The sensor is very difficult and akwquard to get to. Sometimes the sensor gets dirty or bent and tweeked just a tiny bit when installing it, causing its' intermittant/insufficient signal not to be read or recognized by the PCM, which takes data from the CMP and the CKP, and based on this data, tells the FICM(Fuel Injector Control Module) which and when each injector is to be activated. In '03/'04, it is common for the wiring harness to fail at the portion just above the plug, or the plug itself becomes oily and dirty, which will cause this code to appear. The sensor was recalled by Ford, so you might try that if the part has never been replaced. If it has, check the harness or it could possibly be bad again. There have been several instances of the sensor failing shortly after being installed. Mine was the harness. The Ford OEM part # for the camshaft position sensor replacement is F7TZ-12K073-B. That is the current updated part also. Good luck.
Some people will say you need to remove the AC compressor to bet at the sensor from the top, but it can beaccessed from the bottom by snaking your arm up to carefully unplug connector and an 8mm short socket with a swivel, a long extention, and a short extention, will allow you to loosen the single 8mm bolt securing it. My money would be on the pigtail being bad or dirty.