I NEVER anticipated the EGR cooler being the culprit. My engine always ran strong with low ambient ECT's and a delta of 8-10 deg....even towing. I did suspect something was wrong when I cleaned white crusty crap from around the degas bottle. It never puked on me tho and I put over 2300 miles towing my TT down and back to North Carolina last month. My warranty was aproaching the end, so I told them to check the coolaant for exhaust gasses figuring now is the time to to get the head gaskets done if need be. The gaskets were apparantly OK, but the EGR cooler was leaking....Oh well. Glad it wasn't on my dime. The only down side is I'm not gonna get an inexpensive ARP stud job done now and there goes my performance tune. Gonna stay stock now. Btw,how often should I change that coolant filter seeing papa Ford just did a coolant BG flush with the VC-9?