Don't quote me on this or anything, but I'm pretty sure that the TDC sensor is part of the distributor. I'm often at least a little relieved if I see an "intermittent" circuit problem since I'd rather clean and/or repair a bad connection than replace whatever expensive "part" the wiring is attached to.
So I'd round up the wiring diagram info for the distributor and start troubleshooting the wires having to do with the TDC sensor. You may be able to get wiring diagrams out of Autozone's free online repair info. They may also have the appropriate testing specs for that sensor.