Are the wires to the cylinder head (coolant) temp sensor OK? if they are
broken it will be full rich.

Mixture for idle is controlled separately from normal running - that is one
of the functions of the throttle position switch, to tell the computer it
should be idling. Idle mix is somewhat controlled by the knob on the back
of the computer. If it is under the passenger seat you can see it through
a hole in the bracket. I'd unscrew it all the way (It turns through an arc
of about 270° and has detents all the way around)

You should probably get a pressure gauge - the cheapest is about as good
as a good one for this purpose - and adapt it to a ¼" hose barb, which
you can fit to the hose to the cold start injector. Pinch the hose shut
before disconnecting it. Vise grips work OK for this. Probably a 40 or
50 psi max will do. Some auto parts places sell a compound gauge for measuring
vacuum and pressure - if it goes over 30 psi that will be OK too.
--
George Downs Bartlesville, Heart of the USA!