I have the following NANOCOM readings;
P0300 Multiple Cylinders Drive Cycle C, Occurred 4 times, Signal Too High, Fault is currently present
P1000 Cylinder 4 Drive Cycle C, Occurred 4 times, Signal Too High, Fault is currently present
P1000 Cylinder 2 Drive Cycle C, Occurred 1 time, Signal Too High, Fault is currently present.
P0306 Cylinder 6 Drive Cycle C, Occurred 2 times, Signal Too High, Fault is currently present
Nothing for other cyclinders. Nothing for cylinder 8 either.

HISTORY. 2000 P38 HSE. 143,000 mi.
About a week ago the vehicle would be a little rough on idle from start but only after the engine was warm and maybe she was sat for 15 minutes. No idle issue from cold start. Idle getting progressively worse but clears after a few minutes. Car drives fine but Ive put her in shed until this gets resolved.

Thoughts and what needs replacing?

You've got a misfire on cylinder 6 (the 0306 code) with very intermittent misfires on the other cylinders hence the multiple misfire code (0300). You can normally ignore a P1000 code as it will go away after a full set of drive cycles have been completed. Check or change the spark plugs, clear the faults and run it through the drive cycles (Drive cycles are in RAVE, Section 17 (Emission Control), pages 2 and 3), that should stop the P1000 codes from coming back.

TY.
I have old plugs out and am waiting for NAPA auto parts to receive the new plugs at 330pm. Will advise.
There are 6 different drive cycles. Ill assume its C1 or C2, although how I’m going to get 50MPH for 5 minutes on country roads is beyond me……

Yes, C1 or C2 depending on whether you have advanced EVAPS or not.

Haven’t a clue whether I have advanced or not….

If you've got the EVAPs charcoal canister next to the bulkhead behind the EAS box and it has two hoses going into the top of it (rigid plastic pipes), you don't have advanced. If you've got it and it has a third hose coming out of the top and going downwards or you don't have the charcoal filter box but have a box mounted on top of the RH chassis rail, you have advanced.

Ok. Well changed the plugs an now I have a
P0102 Mass Air Flow Sensor
Fault Drive Cycle A
Occurred 1 Time
Signal Too Low
Fault is Currently present

That's odd? I'd clear the fault and give it another go.

Does the charcoal canister need servicing ever?

Mines a 95 GEMs so it's there behind the EAS box. Don't understand what it does though

I've never touched mine and although it is 3 years newer that yours, it's done 469,000 miles. So I suspect not.....

Its used to recover the vapour from the petrol tank, which is then later drawn into the manifold and burnt rather than releasing it into the air when you remove the fuel filler cap.

Thank you for that

Thought I best ask just incase

All fixed and sorted.
Replaced plugs and wires.
Cleaned MAF.
Replaced both coil packs as I had a brand new set from a P38 rebuild. Seller sent me two sets in error and when I pointed this out to him he told me to keep them….’my rewArd for honesty”.
Vehicle is grand now…… until the next demon appears.

I plugged the NANOCOM in to test vehicle as the P38 was giving slight roughness at idle.
Im not sure how to decipher the readings but Cylinder 4 is reading mostly .25 and twice each minute or so it goes to 2.33 or 2.24 +/- .1 for a split second and about 1.23 +/- .3 about 4 times for a split second in the same minute. It will spend time at 0.0. Rest of cylinders are either 0.0 or .25.
There is a slight roughness but no faults showing and no misfires.
Any thoughts?