2003 Mercury Mountaineer 4.6L-V8: When the vehicle is not under acceleration [stop sign/signal, exiting an expressway to a surface street, coasting] the engine will not hold idle, then stall. The steering & brakes are compromised when the engine stalls. To restart the engine, the headlights go dark for a moment...this is a very serious matter. Decelerating from an expressway to a surface street, on a curved exit ramp, at night makes for an out of control situation where the driver can not see because of engine failure! I've replaced the throttle position censor [tps] with no improvement. The dealer offers replacement of parts $1500, and no guarantee of solving the problem. The vehicle is useless to me fore it is a hazard to be on the road...for me and anyone else driving near me.

- West Amherst, NY, USA