2007 X Type S D 1988 ccl

[cross]

Can anyone tell me what should be the idle rpm on this engine please ?
I am getting about 880 rpm on idle and it feels a little high. Engine number 0609201317376G

When on the overun, in any gear, when the speed falls off enough to achieve what should be idle revs, the car keeps going as if on choke

Could this be the coolant temp sensor ?

Any help would be appreciated