Volvo: worlds hardest volvo question, mass air flow, hairline crack

Question
Hey Ray .. I've asked a couple before. I've had my 93 850 to the dealer and a volvo specialty shop for a couple weeks both times.  Each thought it was the computer and possibly the computer that controls the fuel injection .. or the communication between.  they kept getting spuratic codes.  So one shop replaced the computer, the fuel injection controller, the idle air control valve, a couple relays (fuel pump and something else), the cam position sensor, the speed sensor, the water temp sensor, and the mass air flow.  Nadda.  It will idle just fine when you start it, but will die if you try to go anywhere .. until it is warmed up.  Then it runs fine all day.  If you let it sit for a few hours during the day, it exhibits the same problems.  Both shops gave up.  I'm an ex-mechanic.  I replaced the cap and rotor as, in the old days I saw this with condensation with a hairline crack in the cap.  no dice.  So, I put a variable resistor in line with the temp sensor so I could dial in the appropriate resistence to make the computer think the car was warm.  I sat in the cabin and turned the knob and watched the guage move to the middle and tried to start it.  Would barely start and run.  makes sense .. computer thinks the car is warm .. adjusts accordingly .. but the car is cold and runs badly.  Begininng to think only Al Gore and God can fix this.  Any input is appreciated.

Answer
Dave,
I would look for a vacuum leak. Look at the intake hose between the MAF and the throttle housing. Unmetered air. Test the intake manifold and all the vac lines by the throttle housing. Use a smoke machine to fine the leaks. Look at the PCV part of the intake boot carefully there is an O'ring there that also goes bad.
I have also seen at least two cars that had bad wires going to the fuel control unit. So look there very closely. Even look for corrosion. As for poor connection and corrosion also look the rest of the cars connectors like the things already replaced.