SHELBY GT 350 Member
Joined: Sep 2010
Location: see user name
Doubt it has anything to do with the throttle plate set screw. If stumbling at idle, or idle in Drive/Reverse, first thing to verify is no vacuum leaks. Following that would be IAC valve operation.
2001 GT Convertible
All the usual bolt-on's /200 I6, C4
And a few Explorers too... 2008 4.0 XLT 4x2, 1996 XLT 5.0 4x2, 2003 Sport Trac XLT 4.0 4x4