Ok, so I hit a snag. I pulled the old O2 sensor and discovered that it had been crossthreaded. It must have happened when I had that redneck exhaust shop put in my homemade test pipe. I guess it's time to breakdown and get a real one from Daniel. For now, I'm running it without the O2 sensor, and to be honest, I don't think it has run this smoothly in quite some time. Weird? Gene
Not weird. Remember, the injection system is basically mechanical, and all the electronics do is try to add a little delta to that mechanical flow. Take out those extra inputs, and if it's physically ok it just burbles along.
Running without an O2 sensor connected on a US version 328 is very similar to how a euro 328 works (so generally would work OK if the manual tweak is reasonable, as you've found) except for 1 unusual condition -- an extended period of very high intake manifold vacuum. On a euro 328 (and all non-Lambda K/KE-Jet), they have a vacuum limiting valve that prevents the intake manifold vacuum from ever going super high for a long time if you're at high RPM and quickly close the throttle and/or go into a lengthy period of hard, high RPM engine braking (like going down a steep hill with the throttle closed). US 328 don't have (or need) this vacuum limiting device so try to stay out of that condition until you can make the repair.