Strange noise in engine.
 

2000 Grand Marquis. It is a loud horn like noise comming from the engine. It only does it in the winter months. Mostly when the car is cold and hasnt warmed up. It still does it when warmed up but not as much. Mashing the gas stops it but only for a few mins.
Any ideas on what it could be? Dont really have time to take it in to shop. Its my daily driver.