Anybody have this issue?

:
2018 CX-9 SIGNATURE
Thanks for reading, I could use your insight.

Id left the house and been in the car about 3-4 minutes. I was on a straight stretch of road traveling about 40 mph today when I tried to accelerate. Normal outdoor temperature, excellent driving conditions.

When I smoothly hit the gas, the acceleration got REALLY rough, sounded gravely and the car began to shake.

I didnt lose speed but didnt gain any speed either. After about 3-4 seconds, as the car kept going, it evened out and it didnt happen again.

Its worth noting, on three other occasions, the CX-9 has SLOWED down when pressing the pedal down. Twice from a complete stop and once while driving uphill... Im not talking about a slight deceleration, Im talking nosedive. Scary stuff in my little world. It might help to know I dont floor the gas pedal, I mostly ease into it.

Regarding the above three incidents,
I had gotten back from a long road trip and its possible I had some bad fuel in the tank for a couple weeks.

I love my CX-9 Sig. However, this rough acceleration and body shake today spooked me.

If I dont have confidence in a vehicle, its gotta go. And as you already know, this could never be duplicated at the dealership because these have been a rare occurrence.

Those of you who understand how these things work, please chime in. Also, if youve had this happen, Id like to hear from you.

Thanks in advance!
 
Last edited:

sm1ke

Work In Progress..
Moderator
Contributor
:
Canada
:
'18 CX-9 Signature
Yikes. That does sound scary.. I would go to the dealership to log the complaint anyway, maybe even call Mazda Corporate to have a ticket opened just to be sure this will be investigated.
 
Does the vehicle store any codes? That's the first step in determining what may be going on. The dealership should be able to check for more codes that may be available from a generic scan tool. I would certainly bring it in and open a record of the complaint and get it 'on the record'.
 
:
Mazda CX-9 Grand Touring 2016
I've had similar reactions due to water in the gasoline. Try buying a bottle of Heet or other gas additive labeled to remove water from the fuel system. Follow label directions and see if that helps. If it does, great. If it doesn't, you're only out a few bucks. The fuel filter can hold water, and the filter might have to be changed. The additive can't actually remove the water, but it breaks it up so it can pass through the engine. You'll notice really bad fuel mileage because you're consuming liquid that is only part gasoline and part water. That should last for only one tank. This works even if the amount of water is greater than the ethanol on the gas can deal with.
 
:
2009 Mazda CX-9 GT
Bad gas should cause consistent poor running conditions. Sounds like a sensor issue? Possibly intermittent? Check for codes.
 
The first step should be a visit to the dealer. It doesn't matter if they can replicate it or not, they will at least scan the vehicle for codes, and they may even already have a Technical Service Bulletin or procedures recorded for customers who are experiencing the same problem. From your description this could be the engine/transmission, or it could also be the automated braking system acting up.
 
:
2010 CX-9 GT
Thanks for reading, I could use your insight.

Id left the house and been in the car about 3-4 minutes. I was on a straight stretch of road traveling about 40 mph today when I tried to accelerate. Normal outdoor temperature, excellent driving conditions.

When I smoothly hit the gas, the acceleration got REALLY rough, sounded gravely and the car began to shake.

I didnt lose speed but didnt gain any speed either. After about 3-4 seconds, as the car kept going, it evened out and it didnt happen again.

Its worth noting, on three other occasions, the CX-9 has SLOWED down when pressing the pedal down. Twice from a complete stop and once while driving uphill... Im not talking about a slight deceleration, Im talking nosedive. Scary stuff in my little world. It might help to know I dont floor the gas pedal, I mostly ease into it.

Regarding the above three incidents,
I had gotten back from a long road trip and its possible I had some bad fuel in the tank for a couple weeks.

I love my CX-9 Sig. However, this rough acceleration and body shake today spooked me.

If I dont have confidence in a vehicle, its gotta go. And as you already know, this could never be duplicated at the dealership because these have been a rare occurrence.

Those of you who understand how these things work, please chime in. Also, if youve had this happen, Id like to hear from you.

Thanks in advance!
That's probably detonation. The gravelly sound, rough running and shaking, along with the total lack of power are all classic signs. What kind of gas are you using? Try a different station and/or step up a couple points of octane.

I'd take it to the dealer and report what happened. See if any codes were stored.
 
:
2018 CX-9 SIGNATURE
Thanks for all the input.

First, Ill try the fuel additive to clean out the system.

After that, If I have another episode, Ill ask the dealership to run the codes.

I use only non-ethanol fuel, 90-93 octane at a Pure brand station. This could be the source of the issue.

Ill be checking back in and let you know how it all goes.
 
:
2018 CX-9 SIGNATURE
Well, the “Uphill Slowdown” happened again today. Loss of power for about 1 1/2 LONG seconds on a busy state roadway.

I’ve been using nothing but high quality fuel and I always ease into the accelerator. I’ll go to the dealership (I’m lucky to have a good one) and have them check it out.
 
Last edited:
:
2010 CX-9 GT
Does this problem happen when the car is more loaded down (people, cargo) than when it's just you driving?
 
:
2018 CX-9 SIGNATURE
Does this problem happen when the car is more loaded down (people, cargo) than when it's just you driving?
Just me in there today.

That feeling you get when your body is unconsciously bracing itself for acceleration and then everything bogs down is just sooo weird. Definitely not a comfortable feeling. 😯
 
:
2016 CX-9 GS-L
If you had been sticking to a single fuel station, might be worth trying a different one (not necessarily a different the brand) after getting the gauge as low as you can.
 
:
2005 Mazda3
Well, the “Uphill Slowdown” happened again today. Loss of power for about 1 1/2 LONG seconds on a busy state roadway.

I’ve been using nothing but high quality fuel and I always ease into the accelerator. I’ll go to the dealership (I’m lucky to have a good one) and have them check it out.

Did the dealer come up with anything? While reading what you're experiencing, it kind of reminded me of this thread:


Could be a related issue, who knows. Just wanted to pass it a long.
 
Top