Just when you think you have half an idea what you are doing.. I spent the weekend chasing a gremlin I never got sorted out: (ITB 1.8 Scirocco)

My first 3 laps were terrific, the car was running great and I was already seconds under my quickest time ever and then, I began losing power and then at 5700 rpm in 4th the car would stall out and my fuel/air meter went black. If I let off the pedal it would come back. For the race I changed the pre pump (was convinced it was fuel starvation), had the same condition only worse, power loss from the get go and stalling after the car was hot 3 laps in. Put in a new primary pump that night and for the first session the next day.. same thing. For the final race I changed the freq valve and computer, no change and the condition morphed into not being able to go over 5000 rpm in 3rd, 4th or 5th. I then began to realize it was most likely a bad distributor? was not blowing any smoke, I will check compression but am sure it is okay.

Question is, how best to troubleshoot something like this at the track? I think I got off base by thinking the fuel/air gauge was telling me something by going black - I now think it went black because the engine wasn't firing, not that it had gone completely lean? this is such a bummer.

Also, since the fuel pump I took off was still good I will keep it as a spare - I don't want it to rust or freeze up, what would be the best way to prep it for storage? thanks