After 9 mos, FIXED/ Running great!!!..Wait, noo!!!

[juicersr]

Followup to this post several weeks ago:

ok,I need help, 8mos+ Tbitz efi poor running issue

Well, checked CD box thanks to felllow pelican... good shape, but not the problem

Finally drained the tank and replaced gas and fileter and.... she fired right up and ran incredible. I couldn't believe it... i almost started crying for joy! I tore as around the neighborhood, revelling in that crips acceleration and sweet goodness and sound that only a raw track EFI SC has and that i had missed so much from driving my tame Carrera. Visions of spring track days and rides to the mountains danced through my head!oh the joy of having solved the problem! After 15 minutes of this, i came back to earth and shut her off, whistling as i put a block off plate back on the engine that i had taken off. Then, i went to start her for just one more ride before bed, and .... BACK TO THE SAME F@#$%$# PROBLEM,!!!!!!!!! What the F@#$%$?????? Stumbling and poor idle, will not even rev without misfiring. I CHANGED NOTHING between the time that she was running perfectly for the first time in 9 months and starting her back up after a 10 minute shut off, expcept that i had to take the distributor cap off to put the block off plate on. Is this some sort of weird electrical sink or problem with the vacuum line heating up or something. I am really At wit's end on this. This had gotta be somthing really simple.

[juicersr]

Any wild guesses?

To recap:
Green wire - checked and good
All pin and connections - Cleaned and good
Cap, rotors, wire replaced.
02 sensor - replaced

How could this car run better than ever for 15 minutes, then run like sh$$ 5 minutes later after shutdown? One thing i have noticed is that when the car has not been started for a while, the alternator light will come on for a few minutes on initial warmup, which never did before. I have heard the megaquirt EFI is very sensitive to current flucutations, but the control panel says my current remains 12 volts. Is this some sort of heat sink problem? Any suggestions as to where i go from here, or should i stick to typical board questions like how much bling my car should have, or the what type of oil i should use?

[berettafan]

It's all them there electrical thingies you got into her

Looking forward to reading answers!