The PIP in your distributor may be bad. You might need to get a new one.
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