Have a 2009 P71. had 50,000k when I got it in 2011. and just changed out the stock mufflers with flowmaster 40 series or 44 i guess(don't really know guy at the muffler shop is known for sale of knock offs, told him i want real thing.) Problem is crown victoria has 4 catalytic converters. I have the stock piping and tips just changed the mufflers. Will it make a difference if I change to the after market piping versus the stock. I heard my car when the shop guy test drove it after changing the front brakes and it not as loud as I thought. If I cut the cats will I have trouble with the Computer and will the car start running bad. I need some recommendations here.should I just cut the back cats or tell the to rig it for me. Or if they just put the O2 sensors in the the aftermarket pipe. also are the flowmaster 10 series a good idea on this 2009. Any help is appreciated.

Just side notes, I have AFE custom intake,Just replaced 1 front rotor and front brakes, about to do the spark plugs and have two new tires and going to get two more.

 

The Crown Victoria is no longer being produced. It has been made since the 1990s and become valued by officers all over the country. Soon, however, as old automobiles are retired, it will vanish from the country's scenery. You can get a loan for car title if you need a new car.

 

first things first muffler shops ain't allowed to do away with cats they can only replace them. that being said, you can but they can't if you do away with the back two it will help the engine breathe a bit easier but may cause it to run a little richer and burn more fuel. it will also be a little louder. it may not pass an emissions test depending on where you live. btw the crown vics was made since the mid 80's not the 90's. and finally good luck with the car they have always been ford tough cause they had to be