[jstobo]

i just saw this thread and haven't read all of it but here are some ideas. If you have already tried them then I apologize for being lazy and not reading the whole thread.

Your RPM transducer will not effect the normal idle. It may be bad but it will not change the idle adjustment. It just shuts off fuel when the throttle is closed and RPM's are over 1500 RPM. And restarts fuel when Rpm drops below about 1000.

The throttle bodies air screws set the idle on MFI. You must match flow of each cylinder. The idle is only set by these screws. If they carbon up spray Chemtool B-12 (per CMA) to clean. If you cannot set the idle with these screws you are Screwed(he he). If clean then you probably have air leaks and may need some throttle body repair.

BE SURE that the idle is not set by the screw that depresses the micro switch. Unscrew the micro switch screw completely when setting idle. After adjusting idle, screw in just enough to hear the click with the throttle closed.

Contrary to popular opinion the MFI ran pretty lean at idle when new. Just check the CO amounts in the manuals. But my guess is that through wear, adjustments have to be made to get them to run through all RPM ranges. Also modifications of the engine will ruin the MFI exactness as each pump is tuned to the volumetric efficiency of the engine it was designed for. So engine modifications require more compromises. Gus at Pacific told me if you modify your engine to a Porsche spec engine he could set the pump for that engine. But otherwise it would just be a compromise.

Good Luck.