Check your emails
.
First off - you have the 4.6 engine, NOT the cop engine. There is no different engines in the 92 - current Vics, aside from a few intake manifold and cylinder head changes.
OK - the fuel filter was a good start. Here's a few other things it could be. Start with the basics - pull your plugs, and look for things other than normal tan color (such as carbon or oily deposits). If they haven't been replaced in the last year or two, replace them
. Your idle air control motor may be shot, and your EGR may be plugged. Also, you may have a faulty TPS (Throtle position sensor).
If you've had the engine check light come on, there will be a code stored into the memory as to what's wrong with the car, and unfortunately - you have to go to the dealership for Ford's computer to read it...
Good luck with it - Merc.
Stop in at
www.crownvic.net too, and see if the guys there can help
.