Slow down alert - 2005 Mitsubishi Outlander

Your car is designed to run like a well-oiled machine, but sometimes that machine struggles in unexpected places. There’s not always a warning light to alert you of this, but sometimes your car will be driving fine at road speed, only to die when you slow down and stop. If your engine shuts off at low speed, contact a mechanic immediately for a thorough inspection.
Common reasons for this to happen:
Malfunctioning transmission
Low fuel pressure, dirty or defective fuel injectors, or broken fuel pump
Bad oxygen sensor or mass flow sensor
Loose or corroded wires in wiring harness
Faulty idle air control actuator
Clogged or restricted EGR Valve.

Alert on what? Are you referring to a radar detector, navigation system, or something else? Have you checked the manufactuer's website of whatever device to see if there are updates? Often updates are slow to get distributed when it comes to navigation systems.

Sounds like indicator a little metal plate that alerts you its time for brakes!!!

Yes if you check the owners manual you'll find a speed alert function in there somewhere.

check tire pressure

When your VSC (Vehicle Stability Control) light comes on, it means your car has been forced to take evasive action to avoid a dangerous situation. For example, if you're driving on an icy or wet, slippery road, and take a turn too sharp or accelerate too quickly, the vehicle will automatically reduce acceleration or apply pressure to the brakes to prevent the car from losing control. In this situation the VSC indicator light will light up to alert you that the action was taken, and remind you to slow down - or to be extra careful. Be safe!

could be engine mount,axel shafts

When your VSC (Vehicle Stability Control) light comes on, it means your car has been forced to take evasive action to avoid a dangerous situation. For example, if you're driving on an icy or wet, slippery road, and take a turn too sharp or accelerate too quickly, the vehicle will automatically reduce acceleration or apply pressure to the brakes to prevent the car from losing control. In this situation the VSC indicator light will light up to alert you that the action was taken, and remind you to slow down - or to be extra careful. Be safe!

I don't have my manual with me but that is a self-set speed warning. Essentially, you can set an "alarm" to go on when your car reaches a set speed...to alert yourself that you should slow down. To reset the speed alarm, go to the desired speed and hold down the "check" button. Otherwise, just look it up in your manual. It's fairly easy to fix....