Milano FI Problem

["Coddington, Ronald C" <RCoddington@domain.elided>]

Hi Folks,

Need some tech assistance.  Car is '87 2.5 L Milano.  130,000 miles.
Problem is lumpy hot-start or warm start idle which smoothes out after 30 to
180 seconds of operation.  Cold start is fine.  Engine runs smoothly
throughout RPM range when warmed up.  No visible smoke.  Engine sometimes
slowly wanders 100 RPM or so during hot idle.  During lumpy idle after hot
start, exhaust smells rich.  

Some things I have checked:  Cold Start Injector is neither leaking nor
operating during hot start.  Aux Air Device was just replaced (it was
leaking air when closed).  Coolant Temp Thermistor seems to measure correct
resistance when hot (have new spare on shelf so I can change this out).
Plugs are clean and normal colored (not fouled).  Car consumes very little
oil (for an Alfa).    

What I suspect:  Possible leak down of fuel Pressure Regulator after hot
shut down, followed by it being temporarily stuck wide open while
pressurizing system during hot start.  This would give "too rich" mixture
for first few seconds after hot start.  Also when I remove the vacuum hose
to the FP Regulator and suck on it (to check for air leaks) I get a taste of
fuel in my mouth - no actual fuel but a definite taste (leaky  FP Regulator
diaphragm?).  I just picked up a 0 - 100 psi pressure gauge so will do fuel
pressure checks this weekend (I have a shop manual - yes, it is a puzzling
document in places but, hey, this is an Alfa so we expect such things).

OK Alfa experts - any ideas?

Thanks for any help you can provide.

Best Regards,
Ron Coddington
Hamden, CT                 

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