Discovery 125,000 miles, generally runs fine - just stated to act up. Drove in morning about 5 miles, would not start at lunch time and started again later in the day. That night same thing, would not start, later started and then abruptly quit while driving…and started about 2 hours later.
Engine cranks but does not fire. Check engine, battery, and oil pressure lights illuminate while cranking. Weather conditions are typical spring-like wet & damp. From a laypersons perspective, seems something is getting wet and shorting out.
Any ideas?

 

check your battery cables at the starter, and alternater, there could be a loose connection.

 

We need to confirm whether or not you have spark when this happens.
Bring the needed tools with you and when it happens remove a spark plug, reattach the plug wire and have someone crank the engine over while you watch for spark.
Report back what you find.

 

Just had to have my wide pick my up at Advanced Auto...did it again. The guys there are convinced its the Crank Case Position Sensor. I'll go back in couple of hours and it will start. For ~$50-75 bucks is it worthwhile excercise just to go ahead and replace?

Is it hard to do?

 

Not hard, Sounds like thats what your problem is, but I would check for spark when its acting up as suggested, if no spark I would look real hard into replacing the Crank Position Sensor (no Case needed ).

 

Yeah, it sure sounds like the crank shaft position sensor. Even if you weren't having any problems I would say replace it anyways (if original) because they fail all the time on these trucks and it will ruin your day (cheap insurance).

 

thank you!