Phantom Codes and the Grey Camshaft Position Sensor
The Ford 7.3L Powerstroke engine has a great reputation for it's reliability, but there has always been a glaring issue that could leave you stranded. This issue was a problematic camshaft position sensor (CMP) that can cause mulitple issues such as stalling, no start, and cut out while driving. Due to the safety concerns this brings about Ford developed a fix in late 2007, nearly 14 years after it's initial release in 1994. The fix was an updated CMP sensor. Both the early and late sensor where updated but only the 1997-2003 sensor was a recall item.
Shortly there after in 2008 repair facilities started to note a string of #3 and #8 cylinder failures during a cylinder contribution test or percent delta PID readings on 1999-2003 Powerstroke engines. After confirming that the compression was good in these two cylinders the injectors where replaced. Once the engine was running again the same faults with #3 and #8 where observed. The issue was traced back to the new grey CMP sensor. In the pictures below the differences are quite clear between the old black sensor and new grey sensor.
The above captures where taken from the same truck. You can see the change in the #3 and #8 cylinders. In this example on #8 was flagging a code. Every engine will react differently to the sensor, some will show more of an issue with #3. It has been found that #3 and #8 are the most common but Ford has stated that any cylinder can set a phantom code. Yet in some situations this sensor can even mask a faulty injector/cylinder. This is why it is recommended to install an old black CMP sensor to properly diagnose cylinder misfires in 1999-2003 engines. Even though the 1997 trucks used this sensor, the method of finding a faulty cylinder relies on cutting out injectors and monitoring the change in fuel delivery which does not use the signal from the CMP sensor. This is also true with 1994-1996 engines.