My Mazda 3 2.2 diesel shakes when starting up even when using auto stop/start in traffic or at a red light. I took it to a mechanic and they checked the clutch kit and flywheel but did not resolve it. Car shakes especially when the engine is warm. The mechanic changed the drive belt too. Thank you

  • Does it only shake when starting or stopping the engine, but not during normal running? If so, it could be a worn throttle body that needs replacing. Oct 1 at 11:51
  • Only shake when start than normal until stop on traffic or traffic lights when stop starts working and car automatically start again make noise and shake
    – Nima
    Oct 3 at 20:31
  • stop is normal only shake when start
    – Nima
    Oct 3 at 20:39

1 Answer 1


Ask your mechanic to check the engine mounts and replace them if they are worn. Loose or worn engine mounts will cause a diesel engine to shake vigorously when it starts or stops.

Diesel engines have a much higher compression ratio than gasoline engines, so the first or last compression stroke that occurs when an engine starts or stops can be a bit violent. Some diesels have an "anti-shudder valve" that momentarily closes the air intake when the engine is shut down to rarify the air in the intake manifold and make shutdown more gentle. This doesn't work, of course on start-up.

  • Well I did before all engine mount are fin also I took car to diesel inject specialist and they said nothing wrong with fuel injectors.
    – Nima
    Oct 3 at 20:35
  • @Nima I have no other ideas what could be wrong. I suggest that you go to a Mazda dealer to see if they have any 2015 Mazda 3 diesel on their lot and ask the service manager to start their car so you can see if it shakes the same as your car. If others shake the same as your car, you should consider it a normal behavior of this model.
    – MTA
    Oct 3 at 21:36
  • Today I have appointment with diesel injector specialist to find out what is the wrong if they can't find it I will take car to Mazda dealer, I will update you
    – Nima
    Oct 5 at 6:48

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .