2005 Excursion 85,000 miles, full EGR delete, PHP FICM mod & 50 hp PCM tune, CCV mod to the atmosphere. As the title says oil coming from the tailpipe also oil sprayed on the firewall near the downpipe and looks like some to be coming from the sensor at the front of the passenger side valve cover. I'm guessing head gasket or turbo seal but looking for some expert advice.