Okay i live in an emissions testing free area, my cat on my 99 4.2 is totally clogged; can i get away with just putting in a straight pipe (no cat) or will that mess my computer and chit up or what. Any other side effects. I know i stripped my stang of its cats and replaced it with an x pipe and i love it.

 

There are sensors before and after your cats. The computer will detect that they aren't there and truck will run rough.

 

I thought that the 99 were still 4 cat systems.

Are you talking about the first set, or the second, if in fact I have that correct ?

If it is the second set, you can yank them, and put in O2 simulators from Casper Electronics. This solves the problem of the second set of O2 sensors.

The first set of O2 sensors, can't simulate them, that is what the PCM uses for calculating A/F.

If it is the first set of Cats that are trashed, High Flow cats time. If you are going to that much work, remove the second set, put in mil eliminators, and an X pipe and your choice of muffler ( including none ).

Hope I got the year for the 4 cat system correct.

Steve

 

Steve is right. 99 = 4 cats. Need to keep the first ones or it will run like crap if it even does run.

High flow cats are way to go if you think they are a restriction in power for noise.

 

Ok i have a 97 f150 4.6l and i too was wondering if i could just do away with the cats. I don't have to worry about emisions. I just want more power.

 

first off how many miles do you have? If under 80,000...then you are in luck. I had for replace mine FREE just two weeks ago, I have 71,000. So I hope you'll be able to get the same deal.