problems with my 2008 Mazda5

[blue_eagle]

The engine on my Mazda5 suddenly revs(races) with my foot on the brake. I have stopped at a light with my foot on the brake. The car stops normally. After about 3-5 seconds the engine suddenly revs and the car lurches forward. Applying the brakes harder does not help. The only way I can prevent hitting the car in front of me is putting the car into park. I have an automatic transmission. This problem has occurred 3 times that I can recall and twice in the past 3 weeks.
I bought the car used about a year ago. This is the first and only problem I have had.

 

[kw_da]

That doesn't sound safe at all. I'd bring the car into a good mechanic as soon as possible. Is your check engine light on?

 

[Vasy]

Not a fun one to troubleshoot unless you can replicate it 100% of the time in your drive way. You don't want to drive around the city like that.
You would probable need live data monitor to see what is going wrong.
It could be TPS feeding wrong data to the computer, throttle body actuator acting up or something else I can't think off right now.
But I'd drive it to the dealer, they should be able to tell you whats wrong for $100. much less then insurance deductible if you rear end someone or run someone over.
You maybe have them diagnose and replace part yourself or just do it all on-site.

 

[Silentnoise713]

Unintended acceleration!?!? J/K.

Google "pump brakes revs engine", vacuum leak or air in the system? I experience this in my previous Mz5 -very mild. Haven't tried it with the current car but will do so if I can remember. Take it to a mechanic with proper tools for diagnostic. Put it in "Neutral" when at stop light and/or use hand brakes too.


Edit: Nope, current car does not Rev when pumping the brakes.