It'll certainly be interesting when you guys get to the bottom of this issue. I've never heard of an MDS Solenoid failure, but that doesn't mean it doesn't happen. I've heard of several being broken when trying to remove them though.
I, personally, wouldn't start ripping the intake manifold off until I've explored all the external components/wiring in the system. If all that checks good, and that's the last option, off it comes. I'd be surprised if it's something in there.
06 GCO, Dk Khaki, QDII, Flshing Hi 3rd Bk Lt, MDS "ON" Lt, Airtab Vortex Gens, Debadged, Fumoto Drain Valve, BT Catch Can, Chopped EGR Tube, SRT8 CAI, K&N Filter, Sonnax Trans Line Press Booster, SC Tuner W/Adv Trans Tune App, DS Tuner, Cust tubular hdrs w/3 in Magnaflow/Xlerator AP Exh Sys, Bilsteins, SRT Springs/Sways, Cust Eng Cvr, SRT8 frt/rear bumpers, FRI Sidewinder Cam/6.1 valvetrain, SLP 25% UD Pulley, BBK true 90mm T-Body, SOS Ign Coils w/.060 spark plug gaps, SRT Reps with 265/45&295/40X20's.