Its the timing chain guide - take it off by removing the 2 bolts and leave it off. It causes more harm then good.
under the intake manifold, above the oil filter. A prestone hose passes just in front of it, realy tough to replace.
It is a difficult repair because the fuel tank must be removed unless there is an access panel above the fuel tank.
On my 1996 Nissan altima the oil sending unit is located above the oil pan and below the oil filter on the passenger side of the vehicle.
right above the oil filter
== Answer The PCV valve on a 1993 Nissan Altima is located under the intake manifold just above the oil filter. You have easier access if the oil filter is removed. Not so easy...
drop the pan, then the valve body, the solenoid is above that
Disconnect the wire from the sensor, use an open ended adjustable wrench to unscrew it. take a new sensor and screw it in. on a different model (if not a standard sensor) there is a nut and bolt holding it in, use the steps above to replace it
It is located on the back of the engine block just above the oil filter
Above the air conditioning compressor on the passenger side of engine and below the alternator.
The oil filter is located right above the steering rack on the passenger side.
The coolant temperature sensor, on your 1999 Nissan, is located a few inches above the water pump. The sensor will have two wires going to it.
The flasher button on a 2001 altima is above the middle air conditioner vents by the dash. It is a sort of square button that you push in to make them come on and push in again to turn them off.