Hi

Are you sure it is getting a proper supply of gas? A clogged fuel filter
will do this -- usually the car randomly just drops power (it may feel like
a slight bucking). Eventually, it will just stall as the filter just doesn't
let gas through anymore. Replace it and put some injector cleaner in a full
tank of gas.

On one of my previous cars (an old Saab) I eventually found a vacuum leak
that was causing this. The hose appeared to be on the nipple but the nipple
had clean broken off and was just floating around - It looked right but was
floating around just enough to not cause the leak to be huge enough to
stall. Be sure to check all your hoses.
If you are ever fortunate enough to have the car run badly while you have a
chance to look under the hood, you can find something like this by spraying
a shot of ether around suspected areas -- oftentimes the car will run
normally for a couple of seconds, since the ether drives the air out. Just
be careful and not spray it on anything that might be arcing, if you like
your eyebrows :)

Hope you guys find the problem.
Remco

Thank you for your suggestion.

I don't know if this helps anyone else with the same problem, but I just
got the car back from Nissan, and they said that it was definately the
distributor and, even though I have had 2 distributors in the past three
months, it would need to be replaced.  
Nissan states that it is "common" for non-nissan brand electronic parts to
fail.  While this seems odd to me because they said it was not an issue of
compatability, I am thinking about putting in a Nissan distributor and
hopefully this solves the problem.  

Pull out the distributor.  2 cent o-ring will fix the problem.  Hadthe same
problem.

This seems to be a dead topic with no responses since 5/23/05.  However,
for anyone in the future looking at this, here's my story.

I have a 93 Altima with 162k miles on it.  Three weeks ago I was driving
my car and after 45 minutes it started sputtering, jerking, bucking (or
whatever you want to call it).  My car wouldn't run over 3000 rpm and then
it declined over the next couple minutes from there.  It then died on me
and I had to get it towed to a friend's shop.  My electrical was fine and
my lights didn't dim.  The car just stopped running.  

We checked the fuel system and everything was fine.  Fuel pump worked, I
changed the fuel filter just to be certain, and I had 32 PSI over the fuel
rail.  Funny thing was that after the car cooled down it would run again
for almost 45 minutes exactly (within a minute or two) before sputtering
out again.  

I took it to my friend who's a professional and initially we replaced the
spark plugs, wires, and the cap and rotor on the distributor.  Cap and
rotor were after market (non-Nissan).  Car ran fine for a day and then the
next morning stopped again in his parking lot after 47 minutes.  Took it
back into the shop and found that there was no spark going to the wires
from the after market cap and rotor.  Only after replacing with GENUINE
Nissan parts did we get a spark.  Car ran fine for a day and then had same
problems.  The distributor didn't look too bad initially when we looked at
it, but that was the final problem.  

However, we put in two aftermarket distributors and each lasted for only a
couple days before having the same problems return.  The final solution was
replacing with a new GENUINE Nissan distributor which means I took it in
the a.s ($460 US).  At least we got credit for all the other crappy
distributors.  

Some people have luck with replacing the O-ring so I would start with that
first.  However, be advised that my problem (spark and distributor) were
only fixed with Nissan parts.  All the other research I've done points to
this as well.  In total, I've put 80k miles on my car in 5 years.  When
you add this problem expense in, my total expense over 5 years and 80k
miles is $1200.  Not bad for a used car.  I'm hoping to get a couple more
years out of it so it's money well spent...for now.