1997 Nissan Altima - Fluctuating RPM guage and choppy idle?

Question

The car when running down the road at typical speed of between 30 and 50 mph will experience fluctuations, mild to moderate, in the RPM guage and the associated idle of the vehicle, seeming to nudge or lose power slightly going down the road. By driving fast and aggressive the symptoms can be overcome; however, there is definate smell of unburned fuel in the air as you come to a stop. At times when you come to a stop at a stop sign when this behavior is occurring, the car will literally flutter to a stop and go dead. It will immediately crank again but may or may not behave the same way again. Additionally, if the vehichle is exibiting the behavior it can sometimes correct itself if we pull over, turn the engine off, and start the engine again. The problem is somewhat intermittent in that sometimes when you crank it and drive the care seems to be ok; but the next time it is started, it may exibit the behavior. It is growing more frequent in last couple of weeks. The car is driven only for short trips to the market about 5 miles away so it does not see frequent and long trips on the highway. There are no engine lights illuminated on the dash which would point to emmissions related items and the battery and alternator systems have been tested satisfactory. The engine is a 2.4 L 4 cylinder automatic. 1997 is the year model of the Nissan Altima with front wheel drive and 84000 miles.

Answer 1

a bad 0-2 sensor will cause that to happen and wont even throw a code for it in the computer,you might want to have the computer scanned on it though to see if there's any trouble codes on it that might explain this happening,a fuel filter or a dirty air filter can cause the same running condition that you described also,good luck with it,

Answer 2

NEVER EVER EVER EVER EVER EVER EVER  go to auto zone i dont care what that other guy told you to do. always stay away from auto zone and just incase you dont understand autozones parts and most of thier people are c**p. ill bet its your EGR valve. but get your parts from oreillys or napa nobody else they may be a little more expensive but i promise thier parts are better. o-yea dont do buisness with autozone

Answer 3

That extra hundred bucks sounds like a gimmick to me.  If it's only at idle and extremely low throttle, it may be the idle controller, otherwise definitely not.

Probably the o2 sensor, or you have a sticky fuel injector.