Try the "donuts" around the injectors.
Also try tweaking the idle mixture knob on the ECU. Count the number of "clicks" the knob makes so you can get back to where you started.
Look through Kjell Nelin's D-jet Guide
http://www.914fan.net/djet.html, and Brad Anders' D-jet page
http://members.rennlist.com/pbanders for tons more info.
--DD