Slow speeds the engine will just shut down?

SHERRIZB3

MEMBER
1999 CHEVROLET CAVALIER
145,000 MILES

This as been going on for about 2 months-- I will be driving and (not at High speeds) but slow speeds the engine will just shut down. I am able to put it into Neutral start it and put in drive and then it runs. When I am driving the car and apply the tackometer gos down before the engine catches and goes. This seems to happening more often I have replaced the crank shaft sensor.
When the chevy dealer was changing the crank shaft sensor I told them about this problem but it did not happen when they drove the car -- so could not answer.
Please help
Thank you

1 Reply

SQM

MECHANIC
6,383 POSTS

Hello,

It sounds like an issue with either the mass air flow sensor or the throttle position sensor.
Is your check engine light illuminated? Typically, when there is a fault with one of the engine management sensors the check engine light gets triggered.
If so, get it scanned for trouble codes, as it can help with the diagnostics.

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

If the throttle position sensor is failing it may not send correct information to the ECM and the ECM can think that the car is not on or just idling, that can change the air fuel ratio and can shut down the engine.

Keep in mind that a dirty mass air flow sensor or a idle air control valve can have similar impact on the engine.
Usually, those components can be cleaned out to improve drivability.

https://www.2carpros.com/articles/idle-air-control-valve-service
https://www.2carpros.com/articles/mass-air-flow-service

Please let me know of any questions.
Thank you.

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