Drive '03 Disco to work yesterday...all fine...Wont start at end of day..turns over fine..tried to see if it had spark..couldnt see any spark with screwdriver in sparkplug boot and put close to metal...didnt have another sparkplug....Wife come picks me up...Get to work this am and It starts......Fuel or intermittant spark???? I should have knew it was coming ...lunch time yesterday when and got food...took several more revolutions to start when i went. I refuse to let this truck beat me..When its running its fine--but lately its down more thn running...

 

Sounds like crank shaft position sensor, or CKP. Kills spark when hot, pour water on it and it cools off and spark returns. Will eventually fail completely. See attached pages. About $70. Put every screw and spacer back on exactly, alignment is critical. Plug in, let it hang, then mount. Big hands no advantage with this one. Left rear of engine.

 

Do you have any fault codes, if so what are the numbers.
Other wise I would also suggest the crank sensor as a possibility.

 

Thanks guys......I knew you guys would know....This thing will NOT get best of me...And Mike...Yes it has the three amigos and even others...this is getting to a point of mainatance vs effort vs time....This truck will test ya....

 

I wish I read this post last spring.

 

Update................... Changed out the sensor, fired right up!!! Not that big of a deal to change..tight but doable!!! Thanks to all you guys.....

 

Think how much you saved - buy an Ultra Gauge.