Manifold/header/muffler/tail Pipe problems of the 2006 Mercury Grand Marquis

At 110000 miles my engine started to run very ruff,and would die out at an idle,took it to the dealer and was told it has a cracked plastick intake manifold. When I expressed my concern about putting another plastic part back on,I was told they have redesigned the part because of all the problems they have had with the 4. 6 ltr engine and the plastic intakes!.

My 2006 Grand Marquis original plastic intake manifold developed a crack at the drivers side rear intake bolt area causing it to leak antifreeze. This caused me to have to spend $240. 00 to buy a new dorman replacement and install it. Ford continues to use these cheap plastic manifolds despite losing a class action lawsuit against them for this problem. There will be more of these plastic manifold failing in the near future to be sure. This problem should be addressed by a new class action lawsuit due to fords continued incompetence as a manufacturer. My car also suffers from a defective eatc air conditioner control that blows air out of the wrong vents and won't activate the ac. Also a bolt broke on the drivers side front seat due to rust. Also the digital compass has quit working. Also had a water leak in the back passenger floor area.

My 2006 Grand Marquis has a very annoying roaring noise when the tachometer is between 1800 and 2000 rpm. Also at highway speed between 65mph and 70mph which is about 1800 on the tachometer. Very irritating.