once warm, on my st24??

what should it be on roughly?? once mines been running a few min, it stay at pretty much 600!!! too low??? once i start turning things on in the car (lights,fan etc) the revs start hunting! especially if i turn the steering wheel! its actually cut out a few times because of the hunting it does!

Problem? or simply because the tick over speeds to low?

oh and sometimes when the revs come down (say from anything over 4k) it sticks at around 2k, raises ever so slightly then drops to tick over speed? once again not all the time just every now an then?