Jeff,
You might find some help in the publication called
Bosch MFI Repair Instructions, Supplement 2. Some adjustments are apparently available on the Porsche 2.4 engines which change the relationship between the 3-D cam and the follower lever which modifies the mixture control governor. This in turn seems to effect the mixture to different degrees at different RMP levels. The instruction is beyond my level of expertise. I don't know what specific changes you made to adapt your pump to a 3.0 motor but this technique may be adaptable to your pump. According to the manual, these adjustments require an "adjustment bushing ... which is inserted into the bushing of the measuring ring." You are a better man than I if you have all the necessary tools and can follow these directions!
Good Luck!