2001 Disco has a miss / rough idle (it's a spare truck I picked up a couple months ago with a bad trans that only goes in reverse). I figure it many just need a tune-up, as it just has two transmission codes (722 / 1884) when I put the scanner on it to read the CE light. No other codes....probably just a standard wires/plugs issue most likely?

 

transmission codes are very scary. our trucks rarely have problems with the transmission unless the drive shaft drilled a hole thru the side of it....

as for the miss i would start with a tune-up. new 8mm magnecor wires and some bosch +4 plugs.

first i would figure out the transmission problem.

 

The 1884 code will go away on it's own after you fix the speed sensor issue.
As for the roughness, I agree, start with a good tune, wires, a can of 44K and some good gas.