Ok update on this project. I can now pretty well take a Volvo unit and convert it for Maserati 3200 use, and its good, drives well and no errors. I can add contactless sensors to the ETM and this also works although there are some issues with the Sacer sensors which causes fluctuation problems and makes me wonder if a lot of the unstable idle problems are because of a contactless upgrade. I am looking at this and hope to make some design changes to make this reliable, and maybe even try to make the 3200 idle rock steady like it really should be.
I can control the amout of instability at idle, and responsiveness with the machining of the choke profile, and I have what I think is a decent solution.
I have also successfully taken a stock 3200 ETM and stripped it completely and rebuilt it with newer parts from a donor Volvo unit and this also works well, but takes a lot of work. I have yet to do an extended test drive with this one but it looks very promising. The magnet assembly on the newer ones has been changed quite a bit and has an aluminium sheild round it to prevent issues with bits of magnet breaking off I guess, and generally looks a lot better made.
I am building an automated test rig which will instrument every aspect of the ETM including air flow so I can map the modified ones to match exactly the profile of the OEM version, and also measure any sticking and indeed the response time and sensor output matching. This will be ready within about 10 days. This will also allow me to run testing on any throttle body and determine exactly what its doing, and also allow me ot get a level of consistency with these modified ones.
So if any one has problem with their throttle body give me a shout, I have some options, I can replace it or rebuild the old one with newer parts. I will post some of the many throttle bodies I have now (I have purchased 6 now for various experiments, and they all work!!!) on e-bay too so anyone can get these.