Some do, most do not.
Easy enough to look under the back end of the car and see if there is an exhaust on both sides.
According to the 1998 Mercury Grand Marquis Owner Guide : Single exhaust ( 200 horsepower ) Dual exhaust ( 215 )
The Mercury Sable and the Ford Taurus will have DOC in printed on the engine if they are dual overhead cam engines. The symbol should be on the top of the engine.
The 2004 Mercury Sable typically has two catalytic converters. One is located in the exhaust manifold, and the other is part of the mid-pipe section of the exhaust system. This dual setup is common in vehicles with V6 engines to help meet emissions regulations. Always consult the vehicle's service manual for specific details regarding your model.
I don't think are multiple types of catalytic converters.What might be different could be where it's located - dependent on if your car has single exhaust pipe versus dual exhaust pipe system.
On a 1998 Mercury Sable : No , there were ( 2 ) engines offered from the factory The 3.0 litre " Vulcan " V6 ( which is an Over Head Valve / pushrod design engine and the 3.0 litre " Duratec " V6 engine ( which is a Dual Over Head Cam design engine )
there are 4 o2 sensors on the gen.3 sables, one off each manifold, and one before each cat.
For a ( 2002 ) Mercury Grand Marquis : 220 horsepower ( 235 horsepower with dual exhaust )
For a 1998 Lincoln Town Car : It depends on which state it is sold in and if it is single or dual exhaust Single exhaust ( 200 or 205 horsepower ) Dual exhaust ( 215 or 220 horsepower )
In a 1999 Mercury Sable : It depends on which engine you have The 3.0 litre " Duratec " V6 engine is a Dual Over Head Cam design with ( 2 cams on the top of each cylinder head ) The 3.0 litre " Vulcan " V6 engine is an Over Head Valve / pushrod design engine that has ( 1 camshaft )
On a 1996 Mercury Sable : There were two engines from the factory : The 3.0 litre " Vulcan " V6 engine , which is an Over Head Valve / pushrod design engine or the 3.0 litre " Duratec " V6 engine , which is a Dual Over Head Cam ( DOHC ) design
true dual by far
The advantages of having dual exhaust, if it is a true dual exhaust, include increased gas mileage, cooler engine temperature, and more engine horsepower. However, if it is not a true dual exhaust, it doesn't matter how many exhaust ports there are, there will be no advantage.