Car moves when shifted to Drive

ford
acceleration
mustang

#1

When I start the car and shift to Drive, the car takes of @ 5mph without any gas pedal action.



Why


#2

When you start a cold engine, the idle speed is higher than normal. High enough, in fact, to move the car. This is quite normal, unless your car’s cold idle speed is exceptionally high.


#3

It could be because you have an automatic transmission that works as it should. What year is this Mustang? You are not applying the brakes as the car moves at 5 MPH, are you? That would be a serious issue.


#4

Only when parking, 5 mph is fast when in a parking garage. I understand some forward movement is expected. I expected the car to respond when I apply the gas, but it is like the car is on cruise control @ 5mph


#5

Does it do this when the car is at full operating temperature or only when the engine is cold?

If only when cold, it’s normal, as McP said.
If it’s doing it when the engine is at full operating temp, you have too high an idle. There are a few possibilities, but if this is the case post back and we’ll list them one by one…depending on the year of the 'Stang and its engine (carbed, TBI, or multiport injection).


#6

I happens at full operating temp. It is a 2005 V6 convertible… When I slow down all the way, the car still runs at 5mph

THANKS


#7

In that case you may want to look at the idle air control circuit, or maybe even the throttle position sensor.


#8

Looked for TSB’s and none related to your concern. There is a TSB about slow filling of the gas tank (new tank fix). Finally some other reason than “topping off”.


#9

Excellent…but are you sure you attached this to the right thread?