We have a 2014 Mazda 3 hatchback. We've had our car for 2 years. When driving, the car will just stop accelerating. This has happened 3 times to us already. All 3 times we were driving on the highway and all of a sudden the car stops accelerating and will have practically no pick up. The last time it happened, I was driving between 80-90kpm and it dropped down to 60kpm on a flat surface. Going uphill it went down to 12kpm. We have had to have the car towed to the mechanic to be fixed. Last time they changed the spark plugs. Each time they try something else. I've looked online for someone else having this issue and how to solve it, but I haven't found anything. The mechanic said that this is just something that happens every so often, but 3 times in less that 2 years is insane. If anyone has any ideas on what could cause this and how to fix it, that would be amazing. Thanks!

 

Can't say I've ever heard of this issue. What are the OBD-II codes each time this happens?

When the problem starts, if you stop the car, turn off the engine, and restart it, does the problem go away?

 

I am having pretty much the same problem with my 2012 Mazda CX-7. Have had it for 2 years. Went shopping, filled car up with gas, came home, left again about 20 minutes later and after driving the car for about 20 - 30 minutes it started cutting out. The harder you press on the gas pedal the more it seems not to get the gas. Now it stalls and won't start for a while but after you wait it starts. It runs good and then the car seems to starve for gas after about 30 minutes. I can't take it any where because everyone I call tell me they have to have a code but the engine light is not on so they are unable to answer. We put Lucas gas treatment in it and it didn't do anything, put stp treatment in it, and it did nothing, new air filter, and cleaned the mass air flow censor, and did nothing. It took me 4 months to find this car and I really like it. I just started a new job and my car breaks down. I don't want to do what my husband wants me to do which is trade it in. If anyone can think of anything please please answer.

 

The best possible advice would be to stop throwing money at it and take it to a professional for diagnosis.

 

Rena,

Without a code, this is going to be trial and error. Very painful process. Here is what I recommend. Talk to your dealer and offer to give them the car for a week if they are willing to leave the computer connected while they drive it around. It may not throw a code, but if the technician driving it observes the problem, he can record all the current paramters for review. Then they can diagnose.

If you don't want to do that, based solely on what you have said and nothing else, I would replace the throttle body. Here is my guess: your car is drive by wire, the accelerator sends a signal to the TB and a small motor on the TB opens the throttle. What is happening is the signal from the pedal is not being done by the TB either because its bad or a signal is lost. Normally this would throw a code, but you are not seeing it. You did not say it was missing, you did not say it dies, so I don't think its ignition or fuel. So all that is left is air and timing. The TB is the air, so I start there.

Good luck
RGAZ

 

The problem with this advice is you are guessing; it is rare this type of advice (or action for that matter) costs less than a proper diagnosis and remediation.