Freelander 2 (LR2) unstable tick over - somtimes

long story short - a second hand throttle body, new low pressure pump, new high pressure pump, and 3 second hand injectors later it (TD4) actually runs again, however still the same problem as before it stopped. every now and then when you pull up to a stop the tick over will climb or settle i suppose at about 900 rpm - the ecu must do its thing then it will drop to 500 or less - it hasnt stalled since i got it back but has done before the work.
has anyone seen this carry on before? i did put injector cleaner through it with no difference now there is 3 different injectors in it with no difference...
ill go back and update my other open post now

SWalker said:

has anyone seen this carry on before?

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Only when the vehicle in question was entirely out of fuel.
Did you keep the old injectors? Are the new ones clean? I'd be doing a leak off test comparing all the units before considering anything else.

thanks for the reply - i have 2 of the old ones - the new ones i got were like new coming from JJ car parts.
out of fuel hmm air leak maybe? I think you are right i would need to test them.. could be a while