Started my '07 F-150 w/4.2L and 5-speed (3000 miles) the other day after a three-week period of not using it. To my surprise, it blew a very visible puff of oil smoke (blue) out of the exhaust. I haven't seen any smoke out of it before or since. I started it today after a two-day rest and saw no smoke. I checked it out on the road, letting off the gas at highway speed to see if a bad seal was going to let it suck oil into a cylinder and cause smoke, but it didn't. Oil level does not appear to be going down. Engine runs great. Does anybody have any ideas (it's a pushrod engine)? This is bugging me since I've had vehicles with 150K that didn't do that. Now that I know about it, I'll be paying more attention to the exhaust at startup as well as the oil level, although the oil hasn't gone down since it was changed on July 2 (about 1200 miles). I'm thinking it managed to get a little oil from the crankcase vent, but that opens more questions since it's not normal.