Problem with car surging forward while breaking for a light etc.

[playford]

I have a '05 Mazda 3 and I have had this problem for a couple of seasons now. When the winter comes, I start up the car and as soon as I start driving and then stop at a light or what have you, the car surges forward as if possessed. If I do not put the car into neutral, it often stalls out. This is getting worrisome and is potentially dangerous enough that I took the car into the shop to get checked out on the diagnostic scanner, in which case they found absolutely no problems. They didn't test drive the car like I suggested.
What could be the problem here? The car has just barely reached the 100,000 km mark and is due for some maintenance not required previously, such as new spark plugs. I have tried a fuel cleaner but that did not solve the problem and I am hesitant to bring it back to the garage again as I of course am charged a hefty fee for them to not find something.:bang

[Default User]

only happens in winter? does it happen even after the motor is at normal operating temp?

At first i was thinking a vaccuum leak. But it would be all year round. Unless the cold weather made the vaccuum hose stiffen, making the leak more obvious when engime shifts. (possibly also need a motor mount if thats the case)

[bman13]

Not sure where your located but I'm sure Street Performance can help you out on solving the problem and not being charged a hefty fee. They are in Markham.

[playford]

only happens in winter? does it happen even after the motor is at normal operating temp?

At first i was thinking a vaccuum leak. But it would be all year round. Unless the cold weather made the vaccuum hose stiffen, making the leak more obvious when engime shifts. (possibly also need a motor mount if thats the case)

Actually, I don't think it does it after the engine has reached the normal temperature now that I think of it. Thanks for that detail, I am sure that is a clue to whatever it is.