Drove home a '07 V-10 Coachman Mirada (just ~30 miles but with a ~1,000' climb and descent). As I drove the last few miles, I noticed that there was a puffing sound whenever I applied throttle. Sound wasn't there when I started out or test drove the right last weekend. The rig does have Banks headers. Would it be a good assumption that the sound is a header leak? Start by tightening bolts (and is there a torque pattern?)
Haven't worked on engines in several years, and never a Ford.