Cold start problem definition:  Engine temperature and air temperature
around 70-75 degrees Fahrenheit.  Start engine w/o foot on accelerator
pedal.  Engine starts and goes to around 800 rpm (instrument panel
tachometer).  If slight pressure put on accelerator pedal to take rpm to
1500 or so, and then pedal released, rpm drops to around 300 and engine
tried to stall and then picks up speed and then tries to stall.  Slight
pressure on accelerator pedal for a couple of minutes or so, solves the
problem.

Here is what I have done:  New within the past two weeks are new
O2-sensor, new Temp II sensor, and new plugs.  A couple of months ago, I
put in new rotor and cap.  Timing is just ahead of the mark.  I am also
working with backup ECU and I have cleaned the contacts on large cable
going into ECU.  I have checked for vacuum leaks and replaced suspect
hoses and fittings.

Engine is Boston Bob rebuild that I installed in September 2003.  Has
about 40,000 km on odometer.  Just about everything I could buy
new/rebuilt at that time such as distributor and AFM went was replaced
at that time.  A few years ago, I installed a rebuilt throttle body.

Recommendations on next steps would be appreciated.

John