Engine shuts off a idel - 1984 Nissan 300ZX

Engine stall or RPM fluctuates at idle.

This problem is commonly caused by a dirty automatic idle speed control valve and throttle valve. Buy a can of throttle valve cleaner (do not use carburetor spray cleaner!) from NAPA or Carquest (made by CRC chemicals) and spray it into the air intake while the engine is running, use up about 1/2 the can, engine will try to stall hold the speed up, shut it down and let it soak for 30 minutes, restart and blow out the remaining fluid, shut it down and disconnect the negative battery cable for 5 Min's to reset the base idle control

You engine is TBI, It uses a MAP sensor check the vacuum line for crack and make sure yo have a good seal, The distributor also check and make sure the pick up does not have corrosion which causes the relutor to stick. As for the EGR it would cause a misfire, and yes the do fail. I am sticking with the IAC as a problem its a stepper motor and has a high failure rate, chack also the ECT (engine coolant temp sensor) for corrosion that gives false reading.

Trish-if the engine is warm and/or the car has been driven, you should check the oil level after it has been shut down and sits for 5 minutes. If the level is good (within one quart of being full), you need to at the very least change the oil and try to go with a higher viscosity oil. For instance, if you are using 5w-30, get 10w-40 instead. You do not mention how long it has been since you had the oiol changed, what car/year/engine, and this information should be updated so that you can be assisted more thoroughly. If the light is on 'steady' (not flickering) and the engine seems quiet and smooth, it could be a disconnected sender unit or a defective sender unit-get back here if you can and try providing more information.

CHECK THE IDEL AIR CONTROL MOTOR MOST LIKELY

Try turning the key off, setting the emergency brake, and then restarting your vehicle. That works for most vehicles with automatic running lights.

any dash lights on check engine lights have battery alternator tested

check the gas lines for licks

check the vacuum hose on the back of the throttle body and check the EGR valve and all the vacuum lines on the engine make sure they are not loose or off or cracked

the rttles are probably the moumting bushings/ rubbers.joe

Try pouring a little water around the base of the coil while engine running and see if it shuts down.if engine shuts down the coil is faulty Watering can works well for doing this.