All I could suggest is adding some Injector cleaner to your gas, but
Im sure youve already done that.......    

Either it's not getting enough gas or oxygen at idle. I'm not an expert on
these
engines, but there are a few simple things you can check-- do you have the
correct
gas cap? (vented/non vented) Do you have a good inline gas filter near the
engine?
Another thing to check is the fuel pump strength, your mechanic can hook up
a meter
and drive the car around while watching the meter. Might be delivering
enough fuel
at some rpms but not at idle.Could be a non-functioning fuel injector. I'd
also
replace plugs, spark plug wires, distributer cap, make sure the spark is
good.
Check any oxygen sensors (if the truck is 10 years old it's time for that
anyway).

--if you figure it out, please post -- I'm curious!

Terry

Since the problem is taken care of by repeated VERY frequent cleaning
of the throttle body (due to a buildup of `junk' around the plate)
then you know where the problem lies, but not the cause for needing
that service done so frequently.

Only 2 things come to mind, both of which relate to improperly or
totally unfiltered air getting into the throttle chamber and gumming
the plate up.

First, are you using ANYTHING other than a genuine Nissan air filter?
If so, stop it!  Use the real deal.

The other one I've only seen a few times in the shop but given, like
mine, that your Pathfinder is now 9 years old, the problem becomes
more likely.  Have your technician remove the air intake hose (big,
ribbed rubber flex hose that connects the throttle body to the air
intake box) and put a light inside of it while looking at the outside
and see if there is any light coming through while he/she flexes that
hose.  These can (and will in time) develop little slits/cracks
between those `ridges' that will let unfiltered air in and gum up the
works VERY quickly.

Wil