I've heard that I can turn my Mercury Marquis Engine into a police car engine with extra power simply by changing some sort of chip. Is this true? If so, where is the chip and how is this done?

 

depends on the year and it doesn't add much in the way of acceleration as much as it raises the speed limiter to 160mph instead of 110 (I think). The problem with this idea is that you need to replace more than just the chip (engine computer reprogramming for later models or replace with one from an interceptor) to truly get the power. If your car doesn't have dual exhaust, you'll have to install it. I'm not sure if there are internal engine differences (and there may well be). You can however add a cold air intake to 92+ models that are bolt on - off the shelf items (for older models you need to custom build it). That will help get more power as well (especially when paired with the dual exhaust). Check out the performance thread in the Grand Marquis forum for more info. lots of angles have been covered in that thread (if you can't see it, select the drop down for viewing threads "from beginning").