I guess I've screwed up my 420SEL. It started running really badly, and a mechanic told me I needed a new fuel distributor, so I installed one. While I was at it, I cleaned out the EGR passage in the intake. Now it won't start. The F.I. is giving the engine 'way too much fuel, and I can't seem to reduce it with the air sensor plate adjustment. That adjustment screw seems to be stripped out or something; it doesn't seem to want to engage anything when I turn it. When I pull the plugs and crank the engine, I can hear the fuel squirting into the combustion chamber.

Any ideas about what I screwed up, and what I should do to correct it?

Thanks in advance.