Thanks for the idea. I'm Bosch, but there may in fact be something ECU related than I could look into.

Right now, the thing is running pig rich, so after pouring over the FAQ this weekend I'm inclined to look into the engine coolant temperature sensor as it's really the only thing left that hasn't been replaced which could contribute (according to what I'd read) to rich/lean run condition. I'll replace the intake manifold gasket at the same time since it looks as though to get to that sensor it'll be much easier if I pull the intake anyway.

I'd hoped to pull a compression test over the weekend, but between crummy weather and service calls that came in I wasn't able to get any stick time in.