If you're in the passenger seat, the fuel ECU is the metal box to the right of your toes, the ignition ECU is the black plastic box in front of your toes. Sounds like that one is still the original, right?

Sorry about the shorthand. I think ECT abbreviates Engine Coolant Temperature, but I could be making that up. I use it to distinguish that sensor from the gauge sender like you mentioned often gets confused. In your car it has two thermistors referenced to ground, one for ignition computer and one for fuel. That is why I mentioned both pins in the previous post.

The vacuum supplied by manifold to the fuel pressure regulator allows it to reference the manifold pressure instead of the atmospheric pressure, because that is where the fuel is squirting. So the net result is constant fuel pressure relative to the inside of the manifold. I doubt your vacuum hose there is clogged, but it should be easy enough to pull it off and feel the vacuum.

The rpm enrichment is done by the fuel computer increasing the duty cycle of the injector opening.
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Art Benstein near Baltimore