Ok, refresh of the run down of sensors replaced so far...
2002 Bonneville SE with 181k miles. I have replaced (in order):
new spark plug wires
rebuilt MAF sensor (had gotten a code on this)
new fuel filter
new Engine Coolant Temp sensor (had gotten a code on this)
new Fuel Pressure Regulator (pressure check in spec at key on and idle)
new Crank Position Sensor (AC Delco part)
new MAP Sensor (as of tonight)
I had found a post of someone with similar symptoms.
His problem was fixed with a new MAP. This is interesting. About a few weeks before my problems began, the coolant tubes (the plastic elbows that route through the belt tensioner) had failed and resulted in dexcool coolant being sprayed all over this sensor. I had replaced the elbows, flushed and filled the sytem with the green stuff. A little later, I started having these other problems. Now, I wonder if the coolant had caused this sensor to fail (I hope).
Anyway, I've now replaced the MAP sensor. I will keep you guys posted.