Trouble code P0191 means: Fuel Rail Pressure Sensor Range/Performance
The 2004 Ford Taurus has a V6 engine.
The 2004 Ford Taurus has a 3.0 L base engine size.
The 2004 Ford Taurus's engine produces 155 hp @ 4900 rpm.
The 2004 Ford Taurus's engine produces 185 ft-lbs. @ 3900 rpm.
The engine is fuel injected ( no carburetor ) on a 2004 Ford Taurus
In the Engine Bay.
The spark plug gap, for your 2004 Ford Taurus 3.0 liter engine, is .009. Most spark plugs will come pre-gapped.
In a 2004 Ford Taurus : The 3.0 L , " Vulcan " V6 engine has ( 1 timing CHAIN )
At the front of the engine compartment on the drivers side
The PCV valve on a 2004 Ford Taurus should be on the left side of the engine. It plugs into the valve cover at the rear of the cover.
The 2004 Ford Taurus Owner Guide shows ( 5W-20 ) engine oil for both 3.0 liter engines ( " Vulcan " and " Duratec " )
According to the 2004 Ford Taurus Owner Guide : With engine oil filter change : The 3.0 liter " Vulcan " V6 engine takes ( 4.5 quarts ) The 3.0 liter " Duratec " V6 engine takes ( 6.0 quarts )