I got my Disco 96 4.0 manual, 120K, from a friend. It is in a pretty good shape, except a few issues that my friend didn't have time to work on (he sold it for lack of time to "play with it".
My first problem is that every other or third time when I start the engine the MIL light comes on, and I read code P0340, what is Camshaft Position Sensor Wiring. I did some "homework" and learned that it can be anything from bad wiring, loose or corroded contact, bad crankshaft sensor, to bad ECU. I've been told that camshaft sensor itself rarely goes bad.Here is what I did so far:
- I've been erasing the code after starting the engine, then driving the Disco for many many miles and never got the MIL light back until i stop turn the engine and start it once or twice.
- When i start the engine, if it runs perfectly smooth I know for sure it will not illuminate the check engine light. but if there are a few "mis timings" that sound just a little like rough running, the light comes on, or the pending code is in.
- I removed crankshaft sensor (what a PINA!!!), cleaned it, put it back, nothing smart to conclude. The tip of the sensor looks bent a bit, but if this sensor was totally bad the engine wouldn't run at all.
- I looked at grounding around the car and disconnected all GND cables and cleaned the contact. This is So Cal, no rust around the car at all, but these grounds didn't mind the cleaning. No obvious problem point.
- I removed the camshaft sensor, nothing interesting to conclude either. Connector is pristine, cleaned it anyway. I placed it back in.
- i checked all connectors - basically the main harness - all wires that are in the engine compartment and couldn't find any issues. No stripped wires, no molten insulation...

Now i wonder what else can i do to pinpoint the problem? Someone mentioned monitoring the camshaft sensor output with the oscilloscope, first I'm not sure how to do it, second the check engine light gets triggered only while starting the engine, not while running it normally, not even when offroading, where it is bumpy, of course.

I would appreciate help and ideas here. I'm thinking to get camshaft sensor and replace it, i might be able to get a good, used one, for $50-100.
Where else can I look, and what else should I check.
Please, when suggesting something, tell me where is it located also, as I just recently got this car And it looks that it has things hidde din th emost unbelievable places .