Hey guys - those two sites were what I've been using - and couldn't have made it as far as I had without them honestly.
@Stevegrizz and Ali SC3:
-The guy who's previously worked on this car for me (and who used to do a small amount of performance work in Tampa) got up with me last Thursday, and by Sunday night it was sorted out. Apparently there was slop in my left side CAM from loose & worn out shaft bearings!.. which combined with a not fully extending hydraulic belt tensioner was the double whammy of pain my timing was having. Regardless - it's done.... WHEW~!
BUT - now I'm back to the task of the hesitation and idle / stalling issues. My IACV (Idle Air Control Valve) seems to only actuate in one direction... toward the closed position. Currently I'm pulling off the plunger assembly, setting it to about 3/4 open, unplugging the electrical connector so the ECU cant close it on me and driving it like that. But, with it in this condition, there is a noticeable loss of power (bogging) under acceleration, and when you get to cruising speed the car shakes badly forward and backward (Bucking) due to not having the right airflow for that driving condition.
So, I'm back to looking at this thread again:
But WOW is that a lot to get into.
@ 164k miles, my SC400 turned into quite the nightmare of fixes. Leaking Valve cover gaskets, Idle problems and the related; Hesitation, Bogging, Surging and Bucking at cruising speed (or/and in cruise), Timing issues (fixed finally!), ABS light on, Electrical brown outs, dimming headlights and dash lights when turn signals used or windows rolled up or down or brakes applied.... and more LOL - I must REALLY love this car