Hey guys.

I have a question for all the gurus out there.
I ZD30 engine recently grenade, so I put a reco'd ZD30 back in. I have noticed now that if it is started cold (haven't run it in 12+hours) that the revs sit higher for the first 10 minutes. Normally when cruising on the freeway at 100 my revs sit at about 2200, but in the first 10 minutes or so it now sits at about 2500-2600. I told my mechanic about it who had a look, but sure enough it didn't bloody do it when he looked. He said that it was probably just the tacho sticking. but I can audibly hear the change of revs when it drops from 2500 to 2200. it isn't a slow drop either, its instant.

Just need to know if this is something I need to be worried about. Last thing I want is to be forking out another $10k for another engine.

Any advise would be appreciated. cheers