Can it run? Yes. The 99 ford does not use the rear O2 sensor for anything to start the vehicle or maintain idle speed so the car would run and somewhat drive as normal. However, there will be fault codes, there may be missing rear fuel trimming due to no catalyst and thus no rear o2 sensor, there could be backpressure changes affecting EGR(if equipped), engine vacuum, exhaust sound or flow.
FInally, and not least important, that engine was designed to get 25+mpg while maintaining low emissions and not creating greenhouse gasses. ALL of the systems on the car work together to accomplish all that, and the catalyst is a MAJOR MAJOR part of emissions control, and also fuel control based on rear o2 response. It is a federal crime to remove a cat from a vehicle operated on US highways. (SOunds overly dramatic doesnt it? But it is in fact TRUE!). You cant even sell a used catalytic converter legally.(Unless inspected and tested and recertified). Despite what magazines and forums may claim, removing a working catalyst will NOT, I repeat ABSOLUTELY WILL NOT INCREASE HORSEPOWER! Those who argue otherwise are dreamers or liars. If the vehicle was designed to function with the cat installed, the included engine and valavetrain system will flow through that cat at maximum power level (Wide open throttle) with less than .5psi backpressure ALWAYS! If its not restricting, its not robbing horsepower. You cant gain what isnt missing. The myth comes from racers saying they need exhaust flow and any blockage robs horsepower. True, on a 900 horsepower drag racer, you probably wont have enough exhaust flow through a factory cat to maintain 900 horsepower. But if the car is stock, or even lightly modified (cold air intake or minor stuff like that)...then leave it alone, it doesnt hurt, and it actually helps.
Yes it will run but the emissions will be high........will not pass any vehicle emissions test, depending where you are using the vehicle could be illegal!
Answers & Comments
In a word, NO.
Can it run? Yes. The 99 ford does not use the rear O2 sensor for anything to start the vehicle or maintain idle speed so the car would run and somewhat drive as normal. However, there will be fault codes, there may be missing rear fuel trimming due to no catalyst and thus no rear o2 sensor, there could be backpressure changes affecting EGR(if equipped), engine vacuum, exhaust sound or flow.
FInally, and not least important, that engine was designed to get 25+mpg while maintaining low emissions and not creating greenhouse gasses. ALL of the systems on the car work together to accomplish all that, and the catalyst is a MAJOR MAJOR part of emissions control, and also fuel control based on rear o2 response. It is a federal crime to remove a cat from a vehicle operated on US highways. (SOunds overly dramatic doesnt it? But it is in fact TRUE!). You cant even sell a used catalytic converter legally.(Unless inspected and tested and recertified).
Despite what magazines and forums may claim, removing a working catalyst will NOT, I repeat ABSOLUTELY WILL NOT INCREASE HORSEPOWER! Those who argue otherwise are dreamers or liars. If the vehicle was designed to function with the cat installed, the included engine and valavetrain system will flow through that cat at maximum power level (Wide open throttle) with less than .5psi backpressure ALWAYS! If its not restricting, its not robbing horsepower. You cant gain what isnt missing.
The myth comes from racers saying they need exhaust flow and any blockage robs horsepower. True, on a 900 horsepower drag racer, you probably wont have enough exhaust flow through a factory cat to maintain 900 horsepower.
But if the car is stock, or even lightly modified (cold air intake or minor stuff like that)...then leave it alone, it doesnt hurt, and it actually helps.
Yes it will run but the emissions will be high........will not pass any vehicle emissions test, depending where you are using the vehicle could be illegal!
*********= against the law!