Good Morning

Let me update what I've done to the Omni to date.
The following parts have been replaced over the course of last year:
Head & head gasket along with the intake/exhaust and head pipe gasket)
AIS motor and Throttle position sensor, cap rotor and wires
Spark plugs (twice)

No plug fouling due to excesive oil or coolant (it does show an over-rich condition which would confirm the cold engine trouble).

The throttle body does sit on a thick spacer (insolater - not the rubber types that the carbed models use. Spraying areosol at the base while running did not indicate any leakage.

The car is driven about 20 to work one way, mostly on the highway. The mileage last year averaged between 30-34. Now it is between 26-29. I realize that winter and crappy gas will take its toll in the mileage area, however, once the problem is correctd it should help.

The link for the e-bag sensor was exactally what I'm looking for.
A big thanks for that.

As always thanks to all of you who responded.