Surging idle 2003 nissan altima s - 2005 Nissan Altima

turn the idle stop screw down

codes p0506=idle controle / r p m
p0650=directional indicator fault

I have a 2003 Nissan Altima making a humming sound towards the front of the motor at idle in Park.

Not sure if alternator or compressor.

Not rattle from timing cover has to be something Nissan already denies.

the surging and whistling sounds like there might be a vacuum leak that is causing this.recheck all vacuum lines and surfaces were this is a gasket that seals a vacuum source.smooth running and good power off idle suggest this leak only affects the motor at a low(idle)rpm.

Do you have a Check Engine light?

Camshaft and crankshaft sensors are common failures on these vehicles and will give you those symptoms. Camshaft sensor is fairly easy to change (right on top on side of head on drivers side)
Crankshaft sensor is buried on backside of engine way down on the bottom.

yes turn down too around 900

the 2001 altima is what i have and I had the same problem as you. turned out to be a bad head gasket factory used cheap ones for a few years before they found the problem. one way to test this is to get a can of carborator cleaner and spray it around the area where the head meets the block under the intake problem should be around the 4th cylinder or close to driver side. if the head gasket is bad the rough idle will smooth out while you are spraying the head.

I had same problem.It turned out to be intake gasket.If it surges when u come to stop or in park, u may want to look at corners of intake,spray something that burns around intake , if the idle levels out it is gasket.

Hi Jerry,
Is the idle surging?? going up and down, while at idle?? and not beeing nice and smooth, or the RPM's just drop down and the car dies?? You don't want to touch any of the factory settings on the throttle chamber aka idle screw on the throttle body. That's factory set for life. You may have a IAC -AAC valve problem which a "air volume control valve". Buut let me know first, what you find as far as the "surging up/down goes", but it doesn't die.