Another thought on the electrical side - if problem seems to improve after warm up; how about using a can of brake parts cleaner or circuit cleaner, which will cool off things it is sprayed on? You could spray injectors on by one. The cam shaft position sensor. The fuel temp sensor. Etc. If the sensor is heat sensitive, this old TV repair trick might help.

 

I just read this on a board and I'm gonna give it a try for my 1313:

"been working on land rovers for 20 years and the problem you have may be a vac. leak at the intake manifold or in one of the hoses,go to your local parts store and get a couple of brake clean and spray around engine intake and hoses if rpm changes wile doing this you have a leak. Also remember that the land rover V-8 is made of alum. and expands and contracts with heat usually the intake is the culprit check all vac. hoses especially at the cruise control servo that hose will break and you will have two problems codes and no cruise control"

I have problem codes (1313) and no cruise control.

 

While vac leaks are always a threat, cruise vac is from cruise vac pump, not intake. But being that Murphy's Law is a mult-volume set, you can have both. I think Eric's problems may be related to the way Disco counts codes, and factors in "drive cycles" which are starts from cold engine. If he clears code after cold start, the rest of the day the engine may not cool off enough (temp) or long enough (hours) so the ECU does not increment the "drive cycle" counter.

 

I will be glad when this "ghost" phenomena is finally identified, if ever.

 

ET - note that on page 81 of the GEMS manual it says that if the cam shaft position sensor fails, knock control is disabled. I would take this to mean that if the camshaft position sensor is unplugged, the truck will run (with default values) and the knock sensors (which can vary timing per cylinder) will be disabled. So you could eliminate those two styles of sensors from the what if column with a simple test.

 

The cruise control does not run off of engine vacuum.

 

Ok lets go back to the beginning. When You say rebuild, What did you actaully rebuild/replace? and did you have these faults before?

 

Just an update. Replaced fuel pressure regulator, alternator, and rebuilt intake and fuel injection. No change. Definitely only registers the misfire codes when run from a cold start.

I'll try disconnecting the CPS and see what happens.

As for the rebuild:

Drove 2 days before realizing head gasket was bad. Unknown what codes were present. Decided to rebuild entire engine.

Block and head were resurfaced. Valve job done with new valve seals. ARP head studs used with Teflon gasket. Replaced two connecting rods, rings, tappets, push rods, rocker shaft, rockers, cam shaft, main bearings, water pump, oil pump, thermostat, ceramic coated manifolds, all new hoses and cooler lines, IACV, TPS, Champion plugs, Kingsborne wires, and reset ECU.

After that it ran great except the misfire codes so I replaced coil packs, two upstream O2 sensors, CKP, VSS, and injectors. Then rebuilt heat damaged wires, questionable wiring, removed CATs and two downstream O2 sensors, cleaned MAF, and waterproofed ECU.

 

If you were to reset codes, does it do it next cold start or wait another drive cycle? Do IAT and coolant temp sensors show reasonable and correct readings at cold start (ambient vs -40F, etc)?

 

can you give us some more detail on these two?