Kal, first things first. Check for the obvious things like an exhaust leak. It's very easy to do. Go get a friend to stuff some rags into the end of the tail pipe while the car is running. The idea is not to completely block off the exhaust flow, just most of it for a few seconds to increase back pressure in the exhaust system. While he is doing this, look under the car. If you hear an abnormal hissing noise, pinpoint that spot. Chances are you have a leak. It is not uncommon for the Contours to blow out the exhaust gaskets if they weren't properly aligned, so check them carefully. If you hear a leak at a flange in the pipe, CAREFULLY feel around the pipe about 1/2" away from the pipe. If there is a leak you can actually feel the exhaust pulses umm... squirt out of the leak due to the increased back pressure. Please do not burn yourself.
The most common place for a leak is at the front exhaust pipe to front cat flange. The engine does a fair amount of flexing on it's mounts and tends to strain this connection.
Hope this helps.
Jeff
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98SE Sport
MTX Trans
Stone Stock.
