First post. Found this forum while searching for this issue I'm having.

I have a 2022 CX9, only a few months old. A couple weeks ago at a light it felt like my car was bouncing up and down in idle at the light, very strange feeling. But I was on a bridge and a truck next to me so I just chalked it up to that and went on with my day and it didnt seem to happen again. Then it happened last week again, so it got me thinking it wasnt the truck. I was pretty low on gas at that moment too and filled it up and it didnt happen again. But then today its doing it again randomly. Feels like maybe mis-firing or something. At a light the car bounces and feels like a washing machine in spin mode, then it stops. Anyone experience this or have any ideas? No check engine light or anything, I can't get an appointment at the dealer for a couple more days and im supposed to go away for the weekend on a 3 hour drive or so, Dealer says its ok to drive if theres no check engine light but im a little skeptical cause i'll be driving through mountains where theres no cell service for a long time with kids in the car. Thanks for the help.

 

It could be a misfire, it might be a dirty throttle plate or a few other things. I'd swing by Autozone or O'Reilly's or Advance, whatever is near you, and ask them to check for codes. Not all codes set a light. My '16 CX-5 gets a little hitch at times, but that's just the throttle body needing a little cleaning. However, it's nearly 7 years old with 75,000 miles on it.

You are being proactive and that's good. It's how your car will stay in good shape and last. If there are no codes present, check with the dealer and see if some fuel system treatment will void your warranty. If it doesn't add a bottle the next time you fill up. It may just be something simple. If you have the 2.5, I have the same basic engine and it's been cast iron reliable so far.

 

I agree with Grouch. Your previous fill of gas may have had some water in it or other contaminants. Or some component in the ignition system may be failing intermittently. Get the codes checked, and use a fuel system cleaner that lists water removal on the label among its other benefits.

 

I have a 2021 CX9 and mine did the exact same thing today. I was stopped, waiting to cross the highway. It felt almost like the engine was going to cut off as well. With my foot on the brake the car was definitely jerking and bouncing. I made it home and had it towed to the dealer. They can find nothing wrong and no error codes. The car only has 9800 miles on it. IDK what to think .

 

The next time it happens make a video to show the service manager at the dealership. Don't stop with the service writer, ask for his manager. Ask the manager to bring in a lead mechanic if possible. Show them the video and leave the car there. They have contacts in Mazda North America that might know the cause and the fix.

 

1. Did you ever find what was wrong with it?

 

After the 4th time of it happening (feels like Incredible Hulk is shaking it) I took it into the dealership. They couldn’t replicate it and checked the brakes and sensors and found nothing. It happens with a car in front of me and without anything in front. At first I thought it was an earthquake or vibration from a semi. Will only stop if I move forward some and brake. Very unnerving especially if you have someone in front of you or you are at an intersection.

 

I’m having the same issue with my 2021 Mazda CX-9 Grand Touring ! No codes, lights or notifications on MyMazda app. I got gas two days ago and have had no issues until today with it down a quarter tank. I’ve also had issues with the oil evaporating. The first two times I had to take it in because the oil light came on, and sounded a loud alert telling me to pull off the road immediately and have it serviced, they told me there was nothing wrong. The third time they finally admitted that Mazda is aware of the issue and are working on a resolution. I just had it serviced two weeks ago. I’m starting to think it’s a lemon.

 

In Australia, there is a service bulletin regarding one of the engine mounts to fix CX-9 vibrations @ idle.

 

Thank you. I'm not sure if we'll have the same capabilities here, but it's worth a call to Mazda.