if you did your first oil change at 1000 miles and changed to synthetic, that might be your problem as the engine is not fully broken in at 1000 miles, it takes longer than that for the rings to fully seat and synthetic provides "too much" lubrication for proper break in. also, the dealer saying that it is the injectors might not be them blowing smoke up your *** because injectors can be loud.
2011 F-150 4x4 SCAB XLT, 5.0, 3.73 E-Locker, Off road, plus, convenience packages, adobe interior, captains chairs, Leer 100XL, Bedrug, Toyo Open Country ATII Extreme 285/75/17
2001 Ford Mustang GT Bullitt, 5.0 stroker, 10.6:1CR, ported PI heads, long tube headers, off road H, magnaflow catback. 320hp/335tq