93 D15B7 fast idle
 

Long story:

1) Head gasket blew in 2007
1.5) Drained old gas, replaced with new gas and some sea foam.
2) Replaced with non-MLS gasket and new head bolts (sat until 2011)
3) Put together and tested, found low pressure in 2 cylinders
4) Took apart again and lapped the exhaust valves (intake looked good, looking back I should have done both)
5) Tested valves by poring gas onto the valve seat side, no leaks
6) Put together again with new MLS head gasket and same new head bolts
7) Runs rough put good pressure in cylinders
8) Pulling plug wires, #2 made no difference in performance of engine
9) Tested for spark, found good spark in wire and plug
10) Tested fuel injector, failed, replaced
11) Runs ok but with fast idle
12) Re-checked timing, was off quite a bit (with timing circuit thing jumpered)
13) Tried to adjust timing, ended up moving belt 1 notch to come close
14) Adjusted idle adjustment screw to lowest setting
15) Re-checked timing, was off, moved belt back 1 notch
16) Rinse and repeat a few times, finally got timing right on, idling at ~550
17) After driving a couple of days its now idling high >1000 by my guest

I took apart the Idle Air Control Valve (IACV) and started cleaning it and plan to do the same for the Fast Idle Valve (FIV) if I can find it.

Questions

1) Can I test these different valves (and the TPS) with a multimeter? (Links or instructions would be helpful)
2) If cleaning the IACV and FIX doesn't fix the fast idle, any other ideas on what to check for when the sympton is fast idle and doesn't go down when engine warms up?