Anybody know what the fix is for my 2007 Mercury Montego Premier? When the car is in drive and the car is either stopped or at a slow speed such as at a stop light or pulling into a parking space, the car lurches forward. It is almost as if the computer is telling the car to step on the gas. I am concerned for my 16 year old daughter to be driving the car and have the car suddenly accelerate and get into a collision.
Is the check engine light on?
How many miles are on it? What is the state of maintenance? Plugs, wires, filters, etc?
You say the car is lurching forward. Is the engine actually revving up? What does it do if you just sit at idle in neutral or park? What if you just sit at idle in neutral or park and hit the brakes?
The check engine light is not on. I have almost 89,000 miles and my mechanic told at my last oil change a few weeks ago that the plugs, wires , filters and such were all fine. It only does it when the car is in drive and yes, it actually revs up regardless of whether your foot is on the brake or not. I read somewhere on the internet a few years ago that other Montego and Ford 500 owners have experienced the same issue, but no one could explain it or provide a fix. I have always wondered if it is a glitch in the onboard computer’s programming.
If the engine does actually rev up, but won’t do anything funny while you’re just sitting at still at idle then my first guess would be a sluggish/sticky idle air control (IAC) valve. This opens up when your foot comes off the throttle to control the idle and should close back down when you are on the throttle. If it sticks open a little or otherwise gets a bit squirrely in transition it will be sucking air when its not supposed to. The computer will “see” the air & deliver the fuel & the engine will rev.
These can be cleaned and even if that doesn’t help, its not really a bad maintenance move anyway. Its not “routine” maintenance like oil changes or spark plugs, but its easy & I wouldn’t count it as $$ wasted if it doesn’t “fix” anything. If you have any mechanical skills at all you can probably do it yourself in less than an hour for about $7.
Thanks. I will look into it.