Bought a 2005 Excursion XLT Powerstroke with 151,000 miles back in June. It already had an upgraded stud kit, upgraded EGR and Oil Coolers and a bypass coolant filter installed. Ran it for over a month and put 500 miles on it before I got a P0401 code. I immediately pulled the EGR valve and IAT2 sensor and cleaned them both. The valve wasn't that bad, but it did stick a little bit even after a thorough cleaning. I figured that must be it and replaced it with a new EGR valve. Several hundred miles later the code came back. I cleared it and it stayed that way for another several hundred miles before it popped up again. Cleared it again and it hasn't come back yet but I'm feeling like it's just a matter of time. I haven't noticed any impact on engine performance. Just pulled my travel trailer a couple hundred miles with no problems and no codes. No other codes have come in. I was thinking to use some contact cleaner on the connectors and see if that does anything. The wires appear to be in good shape. Is there anywhere else I should be looking? Anyone else had similar problems? Any help would be appreciated. Thanks in advance.