According to the GEMS service manual if it will not idle but will run as long as the engine rpm are kept above 550 rpm then it is a bad idle air control valve.

 

Symptoms seem to completely match mine. Plugs and wires are the cure. At mechanic this about 600.00. The heat the engine creates causes the wires to degrade quickly. Atlantic British will have the parts.

Patrick

 

Any update on this? My Rover is doing the same thing. 1998 Discovery. It is not fuel, it is ignition. Watching the timing light it just cuts out when you rev it up. Idles fine.

 

I changed the speed sensor on the transmission and it fixed it.

 

VSS is under the vehicle, between the transfer case and the parking drum (drivers side). its a pain to get to but easy to rebuild (See the thread in the tech section).

Mine did this where it was bouncing between 2000-3000 rpm in spurts when my VSS was bad.

Easy test, unplug the VSS and see if your truck drives normal. You will loose the speedo so have a GPS or something for telling your speed.

someone else can speak to the crank sensor.

EDIT: should have looked for page 3... ahha

 

You're issue is probably different..... the VSS is only an issue if your vehicle is actually moving