throttle body replacement..

There is a micra on sale that requires a new throttle body, i need to know how i'd go about getting it replaced.

Would i need to find a new throttle body and bring it to the mechanics?
Or would the mechanics have one already?

How much should the parts and repairs cost?


or even better - how hard is it to do it myself?

Not a difficult job to do yourself at all...

If I recall correctly:
Loosen the clip at the top of the throttle body and pull the air filter assembly off.
Pull out all of the plugs on the throttle body.
Disconnect the throttle cable and coolant lines; and
Undo the four cap head bolts.

You can get new throttle bodies off eBay for $150 or so but I'm not sure about their quality. I would think a genuine nissan one (if they're still available) will be in the region of $500-$1000. Best bet is probably to find a good second hand one...

Replacement is the opposite of removal with the exception that you may have to adjust the idle which is done with the black plastic set screw towards the bottom of the throttle body (can't miss it).

All that said, what is the actual fault with the existing throttle body? Maybe try cleaning the MAF Hotwire, cleaning all the connectors, and following the re-soldering guide on the forum before you do anything else...