Sounds like it could the the Idle Air Control Valve. Looks like this:

http://partimages.genpt.com/partimages/347139.jpg

It should be located on top of or on the side of the Throttle Body. Should
be a pretty easy swap if you want to do it yourself. It will run you $134
from Napa. Sure beats the $370 at the stealership.


"Don" > wrote in message
. ..
> After my car has warmed up, and idles around 750 rpm, and I come to a full
> stop, the idle is smooth for 10 seconds. Then the engine stumbles, the
> idle
> dips down to 250 rpm for 2 seconds, almost stalls, then the idle goes back
> up
> to 750 rpm. I have new spark plugs, spark plug cables, clean air filter, (
> there is no fuel filter, except for the one inside the tank(brillant,
> NOT!)).
> 5 speed manual, and my mechanic (at a Nissan dealership) claims to have
> tested
> the fuel pressure, and sez it's ok. He wanted to change some valve for
> $369,
> but said he wasn't sure if that would fix the problem, so I declined. Any
> ideas?
> -Don
>