When Does It Stall? The first thing we ask people is when the stalling happens. The answer narrows things down fast.

• Stalls at idle when warm? Probably an idle air control or throttle body issue
• Stalls when you come to a stop? Could be a CVT problem or a vacuum leak
• Stalls during hard turns? Often, a fuel level or fuel pump issue
• Stalls right after starting? Mass airflow sensor or fuel pressure
• Stalls randomly with no pattern? The crankshaft position sensor is a strong suspect

Crankshaft Position Sensor If your Altima has stalled out of nowhere and started right back up as if nothing had happened, write that down. That's the signature of a failing crank sensor. The engine loses its timing reference for a split second, dies, and comes back when it picks the signal up again. Sometimes a check engine light comes on. Sometimes it doesn't. The car might run fine for weeks between episodes, then stall three times in one drive. We see this a lot on the 2002 to 2006 Altimas, but newer ones aren't immune. Throttle Body Buildup The 2.5L four-cylinders get carbon built up around the throttle body over time. The car starts idling weirdly. Surges a little at stops. Then it starts dying at red lights. Cleaning sometimes fixes it. Other times, the throttle body needs a relearn with a scan tool after cleaning, which is the part most DIY attempts skip. CVT Transmission Issues The CVT in mid-2010s Altimas has a reputation for a reason. When these transmissions start failing, one of the symptoms is a stall or near-stall when coming to a stop. The engine bogs down as the transmission can't disengage cleanly. Fuel System Problems A weak fuel pump or dirty fuel filter can cause stalling that gets worse over time. You might notice the car cranks longer than it used to. Or sputters on the freeway under load. Eventually, it starts dying at idle because the pump can't keep up. Why You Don't Want to Wait Stalling isn't just inconvenient. It's a safety problem. You lose power steering assist when the engine dies. Brake assist runs out after one or two pedal presses. If it happens while trying to merge onto 580, that's a real situation. Most stalling causes also get worse, not better. A crank sensor that's failing intermittently will eventually fail for good. A CVT that's slipping a little will slip more. Catching things early is the whole game. If your Altima has been stalling, bring it by Driven Auto Care in Castro Valley. We'll plug in, take it for a drive, and figure out what's going on.