1999 4Runner Random Engine Stall

We have a 1999 4Runner with the V6 engine, auto tranny, and 230k miles. For going on a year now the engine will occasionally stall when at idle…usually happening at stop lights. The engine starts right back up. This may occur once every other month or once a week for several weeks. Stalling has occurred with warm engine and cold engine, during raining/damp period and when dry. Never has the check engine light come on or has it generated fault codes. Dealer can’t find anything wrong. We’ve replaced Air Idle Control Sensor (OEM), Throttle Position Sensor, Mass Airflow Sensor, and cleaned the throttle body. Plug wires and timing belt were replaced a couple of years ago. Other than this one issue it runs great. Open to suggestions for what to try next.

When it dies, does it start back up easily?

Do the rpms jump?

Assuming all the suggested routine maintenance is up to date. Could be something wrong w/tranny, but I doubt it. My guess is you still got some gunk build up on something in the throttle body area. Did they completely remove the throttle body from the engine compartment to clean it?

The stalling might be caused by a faulty crankshaft position sensor.


The crank sensor informs the computer whether or not the engine is rotating. If the computer loses the signal from this sensor for only a second, the computer see’s no reason to operate the ignition and fuel systems and the engine shuts off.


Having similar issues with my ‘05 4Runner. Runs fine for two weeks then sputters and dies on idle and even while depressing the accelerator which would point to a fuel delivery issue. Got new fuel pump and filter as well as a new battery. Mechanics at two shops are stumped. Codes that came up are p0456 and c1201 neither of which make much sense. Any thoughts?