Alfa Romeo Repair: Alfa 75 high rev problems, throttle position sensor, fuel injection system

Question
We have a endurance racing team racing a alfa 75 TS 1987 model. When racing, we often need to run the engine at high revs but it gets symptoms similar to rev limiting at 5200 rpm. This fault is intermittent and VERY irritating when trying to overtake somebody :^).

Any help would be great as we have NO idea.

Answer
Too bad I cannot be there--what a great diagnosing problem.
I suspect it is a fuel rather than ignition problem. First check is to run a plug cut: run at 6000 rpm for a minute then kill the ignition and coast to a stop and look at the plug insulators--color will tell you the fuel mixture. Your symptom would indicate a realy lean mixture and the plug check will confirm or deny this.  If you are running the stock fuel injection system then this is what you should try next: 180F thermostat (or a restrictor in the thermostat housing), an MSD
map sensor and a careful checking of the throttle position sensor.  It will not hurt to use an MSD ignition box also.

After that you can try disconnecting the o2 sensor or

changing to the $180 version or putting a 1/8 ohm resitor in line.  

If you want more send details of how restricted you are with modifications and which fi version you are using.