Phil,

So I'm still looking at stuff. Hopefully getting closer.

After replacing the ECTS and still no joy in whoville, I went dark and performed the following:

0) Heated the car up as usual, waited 10 to 15 minutes, and then attempted to start the car, at which point it did not start, so...

1) replaced ECM with another one, and the engine fired up and ran for shit. Wrong year ECM!
2) replaced Original ECM, and car started right up, even though it had only cooled down for 10 to 15 minutes since the original shut off.
3) removed and replaced relay 2/32 and 2/53, Car again started right up and ran.

So now, the car will start up and run fine just as before, but now I can not get it to die on command like before after a 10 to 15 minute cool down. There is however a new symptom that is present. After the car has cooled down (10 t 15 minutes) I can start it just fine, however, if I smack the throttle from idle to say 4000 RPMS several times in succession, there is a minute hesitation that occurs and I think eventually goes away, but I will verify this tomorrow. As for the Crank Position sensor, it was replaced in 2018, so I'm not even digging into that, as was the CAM position sensor.

Tomorrow's festivities are as follow(s):
1) Attach fuel pressure gauge one more time to be used later.
2) Install my noid light into each injector to verify that they all do indeed work, or at least that I'm getting a signal there.
3) remove throttle body, check resistance of TPS, and then clean the throttle body, and then reinstall it.
4) Run car through warm up test, then shut off and let it cool for 10 to 15 minutes.

At this point there are several things I want to look at: Fuel pressure, how long does it take to bleed down, are any of the spark plugs wet (Yeah, I know, KlausC asked me to check this earlier, I'm lazy!), check the injector signal again with the NOID light, and will it start again after 10 to 15 minutes. I'll keep track of everything and report back.

My leaning right now is a cold solder joint within the ECM. I have a friend who is a Electronic Technician who can look at all the connections under a microscope and determine if in fact any of them are cracked. If there are, then he will reflow them and most likely we will be back in business and we'll call this one done.

I'll report back later in the week with results as I'm pretty busy this week.

Thanks to Phil and KlausC for asking great questions and pointing me in directions that I may not have wanted to go.

Regards,

Matt
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1989 - 245, 1990 - 245, 1991 - 245, and 1993 - 245