Sorry for initiating a thread when this is a direct followup to my one about the erratic idle but all my good intending has given me a bigger problem now. (I also apologize for the length of this, but I list every step that I did here for total clarity):

[Basically, all I did was remove/clean the throttle body, accidentally start the car with the throttle switch and a hose disconnected, and tinker around with the base idle set screw]

Totally new to this part of my car, I went ahead and cleaned the TB after removing it, even taking off the bypass valve manifold and giving the plug at the end of the screw a light cleaning. Soot to be found in both places, but nothing extraordinary (not like an old flame trap, i.e.). I did my best to avoid getting carb cleaner in the hinge nearest the idle sensor switch, which was clicking from the beginning and still clicks in the present; I avoided metal on metal and used a clean rag and toothbrush to get everything cleaner than before, although certainly sub-sanitary. I cleaned the flame trap while I had the TB removed, even though it was relatively clear compared with how I've seen it before. I checked the hoses leading into the TB for cracks and made sure the passages were clear before reinstalling. The TB got a new gasket although the bypass manifold/thingamajigg did not. I'm 90% sure that I put that back correctly. I did get a couple of blasts of carb cleaner directly on the interior of the TB despite my knowing better/precaution, but whatever sprayed onto that hinge nearest the idle sensor switch was wiped off within a few seconds as best I could.


The first two times I started it died immediately so I killed the engine and first connected the dangling throttle sensor switch wiring harness (doh!), it didn't even start up again, so I (doh!) connected a loose vacuum hose but to no further avail. I then disconnected the (-) terminal of the battery for 15 seconds and gave it another go -- SUCCESS. It started up and ran now but the idle was TOO HIGH instead of too low as before my 'repairs' -- it would also stutter and drop to 500 or so as I was revving at 1500 rpm (as per the BENTLY instructions for setting base idle), looking like it would stall. This would be every 6-20 seconds I'd guess. Since I could find no more loose vac hoses that would cause a high idle I then tightened the bypass valve on the TB, which was in a guesstimated position after my cleaning. Turning that plastic screw lowered the idle at least back down to 900, so revved it again at 1500 and it completely stopped hiccuping for those five full minutes. I then proceeded with setting base idle by grounding the white-blue wire on the blue test plug at the inside fender, making sure it was NOT the pink one, then turning the bypass screw a tad. I got no response from the engine, so I tinkered with the screw some more either circuit (I thought that I might not have been making a good connection with the ground), starting the car with it grounded and it it open, and quickly the engine lost its smoothness and started idling erratically once again.

Now it will start and then quiver a few seconds, the tach needle jumping down from around 900-1000 to 500 or even less, before dying completely. With my foot on the accelerator it doesn't last much longer either, maybe ten seconds. I just went out to start it before typing this and it wouldn't even catch without me giving it some gas.

Another noteworthy factoid: The idle stops are completely touching at either end, neither have a gap, nor did they before any of this happened.

I can only guess that: (1) I fried my ECU by starting the car with the throttle switch disconnected; (2) I damaged my throttle switch with 0.2 mL of carb cleaner that leaked in through the tiny opening in the throttle body; (3) There is a fine line with all those TB adjustments that I'm being too sloppy with; (4) I did everything just fine and now I have a completely different problem whose coincidence is unrelated.
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These are the only things which I did to an otherwise working car that ran pretty much fine this morning. ANY ideas I will GREATLY appreciate hearing. Thanks for reading!!