Your Accessory Drive Belt may be slipping. This is often due to a wobbly pulley (water pump, air cond compressor, oil pump, alternator, Power Steering pump, idler pulley, tensioner pulley) or a weak Tensioner or a badly worn Drive Belt or any combination of the three!
This slip becomes obvious when you turn on the air conditioner (compressor clutch engages putting a load on the Drive Belt) or you start to accelerate from a complete stop or when going uphill. Usually when the engine is on a low gear and the momentum has not built up enough to overcome the load(s) that is placed on the Accessory Drive Belt.
My wife's 2006 Escape had a wobbly Idler Pulley, weak Belt Tensioner and worn Accessory Drive Belt (ribs become sharp or V-like, while new belt grooves are U-like and fat). When I replaced those three the squeal went away and because the belt was turning the accessories optimally (alternator especially) the engine was running with extra oomph! It was not a difficult job to do.
The 2004 Ford Escape has 16 valves.
The 2004 Ford Escape is a gas-powered vehicle.
The 2004 Ford Escape has a 5-speed manual.
The height of the 2004 Ford Escape is 5 ft. 9.1 in. (69.1 in.).
The 2004 Ford Escape has double overhead cam (DOHC).
The maximum payload of the 2004 Ford Escape is 1101 lbs..
The 2004 Ford Escape has a 22 degrees angle of departure.
The 2004 Ford Escape's turning circle is 35.4 ft..
The 2004 Ford Escape has an inline 4 engine.
The curb weight of the 2004 Ford Escape is 3019 lbs..
The 2004 Ford Escape runs on regular unleaded.
The 2004 Ford Escape is 14 ft. 5 in. (173 in.) long.