2004-2006 3.0l had exhaust valve seat issues, so late 2003 may also.
You get random misfire codes, p0300 or single cylinder misfire code.
3.0l Vulcan engine was used from 1986 to 2008, originally designed for transverse mounting in Taurus and Sables, but adapted for use in RWD vans and trucks
Rangers had them from 1991 to 2008
Overall a very reliable engine, not a power house or great for MPG, but it was a runner