Same problem, this was really bad. The car just died, just DIED on my daughter while driving a busy freeway, she had all she could do to pull to the side of the road and wait a terrifying 45 minutes for AAA to arrive. It would not start again until it was towed home. she was so upset. When I finally did get it started, it was shaking like mechanical bull and would not stay running at idle. The good thing is she is safe. It would have been quite a different story for Nissan had this problem caused and accident. I will complain to Nisan and the NHTSA for sure. the only other bit of good news is I did not spend numerous hours or any money on diagnosing the problem. At first I thought it was the fuel pump but I could hear it pumping (pressurizing) during the key on sequence. It did throw a check engine code but not for a misfire, it was for a "lean" condition. I don't remember the number ( I erased it) but it's in line with the misfire code that a defective intake gasket would produce. I had every thought imaginable running through my mind, blown head gasket, bad fuel pump, injectors, sensors, the list is endless, but the intake gasket and all the similar issues posted here make sense. Now, what to do. It's cheaper to fix it than replace the car. I already have new axles, tires, radiator, alternator, tune-up, water pump, etc. At this time of year I'd rather spend $500-800 to fix it than $5000-$8000 grand to replace it with another used car. I'll keep you posted. Hang in there everyone! let's stick together and show Nissan we mean business!

My daughter's Altima does the same thing. Turn on the A/C and it idles like it did when it was new. From all indications it seems to be the intake manifold gasket. The check engine light comes on intermittently.

I did replace the obvious first, plugs, distributor cap, wires, filters and nothing improved. The fuel economy decreased after I replaced those items, which I thought was very strange. I have read many Altima forums and so far from 96 thru 2003 most rough idling was caused from the intake gasket being bad. I read on a few forums where the gasket had been replaced and 3 months later it needed replacing again.