I am going through the same (idle miss when put into reverse or drive...fine otherwise) problem with my mother's car (2003 Taurus LX with Vulcan).
I installed new plugs (old ones had a huge gap), installed a new crank sensor (old one was nasty looking), installed new EGR
, spray cleaned the MAF
(with electrical spray) and cleaned the IAC
Car still acts up. Smooth as silk in park. Can rev up and no misses. I just ordered a new TPS
vac solenoid (old one was dangling).