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:
1. 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.
2. 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 $300
(all-inclusive) to replace them, and I figured that is worth it since
Ford wanted something like $650.
3. 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 :)