I have a 1998 f250 7lug and my state does not do visual inspections and I'm emission exempt due to weight and bi-fuel I was going to remove the cats but was told the computer would not work right is this true?

 

The CATS clean the exhaust gas if several pollutants.
There is an Oxygen sensor in the rear CAT.
The computer compares the response of that sensor with the up-stream front sensor to determine the health and operation of the CATS.
If you remove the CATS, this comparison will fail and a CEL with code will be set permanently. Otherwise the motor should run ok.
The front sensors must remain in place because they controls fuel injection.
Why do you want to remove them if they are working?
There would be no gain in power for truck use.
Good luck.

 

I have replaced all the O2 sensors and the mass air as well coil packs and plugs I get a rough idles still and bad fuel economy I was told the cats are the issue

 

Are there any codes to support the bad CAT issue? code 420 or 430.
Any other codes?
Has there been any back pressure tests done to prove them as a blockage?
If not, that some one is doing some expensive guessing.
It always pays to give supporting info rather than just ask a question like you first posted.
How does the motor act?
Poor acceleration, poor cold starts, misfire etc.
If you want any possible help, we need to know these things and do not trust the opinions of others as you were 'told'.
Good luck.

 

i will put the code reader on in the morning but it has a really rough idle and almost to a stall out, very sluggish while driving and off the line accelartion, i would not even dare tow my dump trailer with it i use my 7.3 for that sucker lol

 

Got the codes P1131 , P0171, P0174

 

I think you need to look for a vac. leak. The 171 and 174 are system adaptive lean condition on both banks.

 

1131 is a bad 02 sensor, the others are both banks running lean. Is your cats are likely fine.

If you remove them, you'll get a code but run fine. However I'd say leave yours in, they should be just fine, and if you do replace I'd use hi flow replacements, not delete them altogether

 

I will further investigate for vac leak but I've changed all the hoses and anything that can be changed last time when I was searching for the vac leak which was that stupid little 90 degree on the back of the intake also I hate emission bull**** it's why I buy older trucks and diesels lol