First, thanks to everyone who posted answers to my questions about the CMP sensor and so forth. I spent some time outside with the scope (actually I tried to get a bit clever; I triggered the scope on the CEL itself in attempt to catch the actual problem). I couldn't see anything amiss, however. FYI here's how the case went down.
This car is up for state inspection in a week, so I took it to my usual shop and asked them to check out EVERYTHING (I gave them a complete list of symptoms and what I'd done). They came up with a little laundry list of problems, and some very weird results:
- Weak battery. The guy swears blind that this one step seemed to fix the P0340. However we agreed to replace the sensor anyway since it wasn't much cost-wise.
- Motor and tranny mounts hard and cracking. Well, I knew this but didn't consider it a major part of the problem. They offered me 0 (all-inclusive) to replace them, and I figured that is worth it since Ford wanted something like 0.
- Oil pressure sensor leaking. Must have been a very minor leak as I have NEVER seen oil under the car.
There were a few other irrelevant things, like needing new front brake pads and the A/C being low on refrigerant (I'm going to defer that fix until after tax season).
Anyway my baby should be back home on Tuesday, all happy and well :)