Ok, been having some issues with the fuelling on the G. I think it's putting itself in limp mode for some reason. When the car is up to temp and the blue sender plug is removded the revs DROP. Also the ignition timing becomes erratic in this state and difficult to set up.

I spoke to Steve at PSD and he said to check the earths, especially the "Earth Block" in the coils loom. But I'm buggered if I can find what he was talking about?

So, does anyone know where this earth thing is? (Haynes wiring diag says Earth Position "In Digifant Loom"

OR

Does anyone have an idea what might cause the revs to drop and not rise when the Blue Temp Sender is removed?

Also! Unplugging the Lambda has zero effect on the idle of the car, should it?

could the earth block be the actual coil itself? as its the only block shaped thing i can think of and it does tend to corrode, I'm pressuming the body of the coil acts as the earth though. I'm sure my cars idle drops when the blue temp sender is disconnected.

An earth block is a common point where a bunch of circuits are earthed, and if it's not solid then this can cause various problems. I'm not sure which point Steve is talking about without looking at my G, but it'll have several earth wires going to it.

if the engine is warm and blue temp sender is removed the ecu goes into service mode which is why the revs change

Shouldn't the revs go up and not down though?

My gut feeling is that the ECU is still reading one sender as faulty and the unplugging of the blue temp sender is putting it into limp mode rather than service mode...

The car is driving well, but I'm concerned that I can't set the ignition timing up correctly due to the erratic idle with the Blue Temp sender unplugged.

the bit steve is talking about is a small metal crimp where several brown earth wires connect together near the ignition coil. You need to strip back some of the loom wrapping on the big bunch of wires near the coil to see it. Then the thing itself will be covered in insulating tape underneath the loom wrap. You'll probably be able to see a bit of a bulge in the thick bunch of wries and this is it. It's obvious when you start unwrapping that bit of the loom.

The only other earth that can give rise to problems is on the inlet manifold next to the lambda probe plug. People often run an additional earth to here direct from the battery. Also, check the original wires earthing here as it's been known for these to drop off and make the car run rather rich(speaking from personal experience here on my sisters GT, took a while to work that one out!)