weird rocco happenings

[amalventano at sc.rr.com (Allyn)]

ok, so im on the way back from kill bill 2 (most excellent, btw).

take 26 home, and put the rieger into a 1.1g drift along the exit ramp 
(right bank).
i bask in the sounds of sliding kumho and occasional per-clunks of loose 
objects finding their way to the driver side of the beast.
end of ramp, no power, absolutely none. no warning lights (still in gear, 
engine still turning). as i am slowing, i figure i caught some water in the 
fuel suction, but this is unlikely (right turn, not left, and i am at 3/4 
tank, and i took care of that water problem weeks ago).
i coast further, figuring whatever it is will pass. i keep the gas planted. 
still nothing.
hit clutch and let it die. cycle key. start. cranks right up.
drive 2 blocks to turn right into neighborhood. hit clutch as i slow for the 
turn. engine dies. i notice the sound of a relay clicking a couple of times 
as i cycle the clutch to try and roll-start. my guess is it was the fuel 
pump relay responding to ignition pulses (an expected action).
roll-start successful as i accelerate out of the turn.
go couple more blocks, slow for left turn, engine dies again. roll start out 
of turn - again successful.
carefully make last turn to house street. this time i stay on the gas and 
keep it in gear. no issues, but the engine doesnt 'feel' as happy as it 
usually is.
i carefully keep the gas on as i drop into neutral and e-brake to a stop in 
the driveway. once stationary, i slowly let off gas to see what the deal is. 
idle slows to a very slow crawl. its a stumbly idle. firing on all 
cylinders, no missing at all, but its a slower idle (~600), and its stumbly 
because of it.
pop hood, everything looks good. do the obligatory check of the idle speed 
set screw - right where i left it. wiggle various connectors, no effect. do 
quick cursory checks for vacuum leaks - nothing. plug wires look good. no 
leaks anywhere. wife comes out to see whats up. i chat while doing further 
inspecting. finally i end up grabbing the throttle body and give it a couple 
of good blips. after the revs, engine returns to a perfect purring idle. i 
mess with it more, but cannot get it to return to its crappy idle.

notes:
- first time it died, i believe i had tach indication, and i believe the 
fuel pump was running, yet engine did not return to running condition 
depsite coasting at 4k rpm with ignition still on. despite this, it started 
just fine after the engine was allowed to stop.
- cause is likely linked to what made the idle crappy, but that doesnt make 
sense.
- it appears the fault is causing the low idle speed, and its also causing 
undershoot of idle if returning from revs, resulting in engine stall.

ideas?

thx in advance for pondering / suggestions
Al