I am having the same problem with shuddering in idle. It is a Mazda CX 5 carbon edition with out turbo. Been to dealership 3 times and they keep telling me to buy gas from a Shell, Sunoco or another high priced gas station. They keep telling me it’s the gas. Well I did what they said on the second visit only for the problem to still be there. I only have 2000 miles on it and it’s a regular 4 cylinder. Since when do I have to buy special gas for a Mazda 4 cylinder. I am at my wits end and have not been able to enjoy this vehicle at all. I even asked them to please give me an upgraded vehicle and I will pay the difference. The dealship told me to claim lemon law and were not willing to work with me. Help with any answers please.

 

I tried exactly same thing but the gas was not a issue. Even worse feedback from the dealer was I should drive more ??? Sucks

 

Our '21 2.5T is sometimes so smooth I can't tell it's running and other times it can be slightly rough. My '20 3.8 V-6 Frontier is the same way. Our '19 2.5 GT was pretty smooth as well. Both used many types of gas without a discernible difference.

 

Unlikely they would with "normal" diagnostic equipment at the OBD connector. GM uses a "Picoscope" to measure vibration and NVH is a fascinating (yet annoying) subset of auto repair. Call dealers in your area and ask if they have a NVH specialist that can look at it and give a more definitive answer. I've seen odd things causing vibrations such as misrouted A/C lines from the factory rubbing the firewall etc. (Not saying this is your problem! Just an example.)

I got to know the Pico quite well during the whole debacle surrounding the 8 speed transmission shudder; GM wanted a screen shot of the Pico showing a vibration of a specific frequency above a certain magnitude to authorize warranty repair. Eventually that was thankfully lifted and we could go straight to flushing the system with a redesigned fluid.

https://www.picoauto.com/products/no...g/nvh-overview