car has no cats runs weird

[fastford1996]

ok i have a 1998 mustang gt 4.6l no mods besides there isnt any cats after looking under the car i believe one sensor is plugged up "o2" sensor and there is one on there no plug and looks to be broke in half nothing comes threw the check engine light besides stuff regarding o2 sensors which i am catless so i expect that but after driving it and it gets hot seems to idle weird cant tell by rpms becuz rpm gauge is retard kinda slow so doesnt show little rpm movements "wud like that fixed also" if any1 has any ideas plz let me know and wud putting a bbk throttle body on it along with cold air intake help maybe flacuate the air to gas ratio? im car smart but only 19 any advice wud be greatly appreciated and if i can id like to do work my self on a budget and i like to.


THANKS, TJ

[fastford1996]

oh yeah but at times it will drop pretty low like 600 rpms and act like it going to die i do see it when it does that bt thats about it. everything else is so small the gauge wont shwo it but u can hear it

[slow86fiveoh]

Well first off u need some new o2 sensors of one is broken and not plugged in it isn't going to run right, they are on there for a reason

[cstreu1026]

Also with no cats you will need either MIL eliminators or to have the rear O2 sensors turned off in a tune otherwise you will get a CEL.

[fastford1996]

Just the rear ones?

[cstreu1026]

yes...the front O2's are before the cats and the rear ones are after. Without the cats they signals they are sending are outside the parameters in the the ECU which is probably causing at least some of the issues.

[700hp04mystic]

Try the iac it will do the same thing u r saying.

[Night/MareCobra]

Mine did this when the iac was bad

[fastford1996]

I took it off the iac looks brand new what is the black nob for i turned it but didnt do anything