MIL Eliminators?

Soo about a year ago i had some flowmaster mufflers put on my exhaust. The guy i went to suggested i cut my downflow catylytic convertors off to improve power and mileage. After doing this, i did not notice any mileage increase. What i did notice was that my check engine light stays on now. When i went to get the computer checked out it said that 3 of my 4 O2 sensors were not fuctioning properly. Im assuming that the back 2 are not reading properly because the cats are missing. My check engine light would come on for a day or two before this exhaust job and shut off afterwards and not come on for months at a time.

I spoke with a friend who did a similiar thing to his monte carlo but he said to fix the issue he installed wat he called "dummy plugs" that shot off the check engine light and increased his mileage by 3-4 mpg. Could these be MIL Eliminators? If so, has anyone ever used them on their crown vic before? All im finding are ones for the mustang which i know has the same motor, but i wasnt sure if theyd work for the crown vic and wanted to know if anyone else has done this. If so do i only need them for the rear downflow O2 sensors or should i get them for my sensors on the front cats as well? Should i cut the front cats too? Will my mileage increase? Or should i just leave it be and drive it how it is?

Any tips are appreciated and thanks.

Try this site: http://www.paladinmicro.com/MustangMILEliminator.htm to make your own MIL eliminators.

All they do is keep the CEL off, and really doesn't solve any problems.

To increase your mileage can be difficult. Loose weight on the vehicle, better air flow in the intake and exhaust (increased size), and lowering operation RPM of the engine (looser gears) will all help to increase mileage. That is why the government pushes for smaller cars with smaller engines. A 5500 lb car with a V-8 gets less mileage than a 3000 lb car with the same V-8. Also, going from a 3 speed automatic transmission to a 6 speed transmission will also get better mileage (if it drops the RPM of the engine at the same speed). Larger exhaust pipes flow the air better than a small diameter exhaust.

Going from the exhaust manifold, if you increase exhaust pipe size to 2 1/2" with good mufflers should help increase your mileage. The problem you have is getting over the rear end without have to restrict (flatten) the exhaust. There are exhaust systems (not performance pipes) that are made to do this, but finding them is hard. I've even seen guys go with 2 1/2" from the exhaust manifold through 2 1/2" mufflers, but put 2 1/4" end pipes over the rear end and then open up to 3" tips. If it works.....do it.

Because of the construction of the cats on GM / Chrysler vehicles, removing the cats or gutting them out improved exhaust flow big time. (Back in the 70s we used to gut out a cat on our GM car and increase mileage about 4-5MPG) But this does nothing for the environment. But some cities and states require you to have functioning cats on the vehicle where other places only make sure the cats on on the car. But the best way to increase airflow through the exhaust is increased size (bigger pipes and mufflers) and straighter lines (less curves in the exhaust).

By getting a "tune" on the PCM to increase your power curve will also increase the mileage. Whereas we old guys had to do lots of little things to control and change the timing and spark advance, now you have a computer that can be programmed to do all these changes. Some speed shops will do a reprogram for about $100, and SCT sells a great handheld unit REPROGRAMMED for about $380. (More information on this at www.crownvic.net) There are programmers who specialize in the CV, GM, and TC as their programs vary slightly from the Mustang and Ford trucks. Avoid those high performance tunes as they will tend to lean out the air-fuel ratio too much besides requiring 91 octane fuel. A good ECONOMY tune will help both power and mileage.

Thank you for the advice. One other thing i heard that i forgot to write in the prevous post is the removal of the egr tube. I have also heard that it can increase mileage. My friend has a 2006 cadillac dts and after removing it, he averages about 30mpg now. I know its gm but would it work on my ford?

Investigate Digimaster 3 tool, reset MIL, change mileage, diagnostic etc for most of vehicle makes