I have a 2000 ram 1500 5.2 and i thought the cat was failing because it started loosing power and went from 18 mpg to 13 mpg so i went ahead and gutted it, bad idea. there was nothing else wrong with it and it ran good, now it will not run for crap and im getting 5 yes, 5 mpg.
I hooked up a scan tool and this it what i got,
STFT is -16.1 @ idle & 0.8 @ 1500 rpm
LTFT is 31.2 @ idle & 15.0 @ 1500 rpm
O2s11 is 0.680v
O2s12 is 1.000v
I guess what i am asking is if i put on a new cat will it fix my problem?
thanks for any help.

 

i don't really know what that scanner info means, but the cat itself has little or nothing to do with how the truck runs. i'd guess that the front (pre-cat) o2 sensor got damaged in the process. i'd replace that first. the post-cat o2 sensor simply monitors the cat, and provides no actual fuel trim information to the pcm, so don't replace it unless you've got a good reason to do so.

 

+2 on that. many of us have gutted cats with nothing but better results in power and sound. that crappy mileage is most deffinaly an o2 sensor

 

Thanks guys ill get the o2 sensor, im getting a new exhaust and i was thinking about single into dual 2 1/4 out with no mufflers, or maby one glasspack before the y-pipe. I am looking for that 70's muscle car sound, what do you guys think?

 

the o2 may be shot yes, so try that first. if you still get the same scanner readings, try going with an o2 sim because at that point its not the o2 that would be bad, its the readings themselves, which you cant change without getting a new cat.