One problem related to car will not accelerate has been reported for the 2004 Mercury Monterey. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Mercury Monterey based on all problems reported for the 2004 Monterey.
The front end of the car was welded improperly and the weather stripping was faulty allowing water to pour down into the car and onto the powertrain control module (pcm) at any time after it rains causing the car to lose power and the transmission to fail. This is a known and common problem among '04 Monterey and Ford freestars. When the pcm is wet it shorts out all transmission shifting and engine regulation. The first time this happened the car would not start or run properly, had irregular engine power, and the transmission would not shift. The engine was trying accelerate even in park. The car had been parked overnight and ran fine the day before, but caused trouble the next day. It had rained during the night. When the pcm dried out the car ran normally again. The second time however, the pcm completely shorted out and is irreparable. The engine runs sporadically and the transmission will not shift out of first gear creating a driving hazard. The car seemed alright until I was on the road test driving and the car would not accelerate, causing me to be stuck going a max of 15 mph in traffic. The car then lost power, forcing me to pull of to the side.