Engine stalling while driving

VISHAV DHIR

MEMBER
2015 HYUNDAI ELANTRA
1.8L
4 CYL
2WD
AUTOMATIC
188,000 MILES

Hi Team,

I recently bought this car. I test drove for around 5 KM's before buying and it was perfectly fine. Before delivery, the dealership offered me free oil, air filter, oil filter change which I happily took it.
After getting the delivery, it ran perfectly for initial 10-15 km's. While I was on the highway and I had to slow down due to traffic, I figured out the car engine got shut down and it's moving freely. As it was first time, I got panicked due to highway, I immediately turned on flashers and pulled up to the right. After pulling, I was able to crank the engine and start. This is still happening intermittently, And I observed this is happening whenever I am at slow speed and my foot is off the gas pedal. As I am use to it now, I am able to start the car immediately shifting the car to N and then shifting to D again once it starts while car is in motion. (Please note, engine did not stall so far while in Park or I am waiting for a green signal at red light)
I contacted my dealer, and he has asked to bring back the car.
But I would like to hear from you what it could be? Should I go for the replacement of this car, or to keep the car if fix is minor?

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

This could be a simple problem so if the dealer is willing to bring it back and inspect it then I would do this for sure.

However, this is something that they clearly need to give you time to drive the vehicle to confirm it is fixed.

As for what it sounds like, this could be a PCM issue or a crank sensor issue so what they need to do is monitor the RPM when this happens and see if the graph drops from the RPM let's 1000 when this happens and if the graph shows a straight drop down to 0 then that is the PCM losing the crank signal so it cuts the ignition off.

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

The RPM should ramp down as the engine slows down. Because even if the engine stalls, it does not just shut off. It is still spinning as it slows down and comes to a stop.

Also, they need to check for codes and see if there are any there.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

If there are codes, then that is going to get us on the right path so let us know what they say, and we can go from there.

Thanks