hey, a while back (about 2 months ago) i took the old cat off and the glasspack and installed a magnaflow high flow cat on the truck with no muffler. it was running great for about a month, then finally the cel light came on and code read something about an insufficiant catalyst..ic ant remember the exazt terminology, but it was the cat converter that threw the code. i reset it and it came back on. if i new that this cat converter i baught was going to make my cel light on all the time, i would have just cut the old one off and just run straights. should i start by replacing the o2 sensors? also, the truck has quieted down since i first put the cat on, hope its not clogged already.

 

Does it still run ok? Not down on power?? If everything else seems ok, replace the post-cat O2 sensor, reset codes, and see if it comes back.

 

yea it runs better than before, just the cel light keeps coming on. but sometimes it seems to run better than others...like not as sluggish. but its quiter than used to be..... can cats get broke in like glasspacks??

 

I always thought glasspacks got louder with age?

If it is getting quieter, that is definitely something to investigate...... For me, it just turned out that I was getting deafer........

 

yea glasspacks get louder, but mine seems to have a little quiter about a month after new cat was installed. ....for example, when cat was first installed, reved engine to about 2500-3000 rpms it would have that loud good poppin sound..even when in gear, right before it shifted afte each gear at top rpms it would have that sound, but now it doesnt, it sounds quieter. it still is loud and has a nice deep rumble, but not like it used to be

 

Or maybe you are getting used to it???? Suppose, you could pull out the pre-cat sensor entirely, and see how it runs that way. if it is 'better', then, yeah, I would start taking a long hard look at the cat.....

If the cat seems ok, just replace the rear O2 sensor, and see if that 'fixes' the code. If it doesn't, do the two spark plug non-foulers trick.

 

if i pulled out the front o2 sensor, wouldnt that mess up the fuel mixture? if it does run better after i pull the front sensor, should i jsut return the cat for its warrenty? and how do u pull the o2 sensors out? i was looking at them earlier, but i didnt want to break anything. are they threaded? should i do that before or after i reset the cel? and what is the two spark plug non-foulers trick? thanks

 

The sensors are just threaded in there. Unplug the connector first, and then just use a big wrench to get it out.

Don't bother resetting the computer first. It will set another code in short order driving with the front O2 unplugged, and removed. Yes, it will mess with mixture, but, it will be running in open loop.... which is does every time you drive it, till the O2 sensor warms up anyway. I am not suggesting you take it to florida that way though. Just cruise it around the block, and see if there is more power that way. (and yes, it will be louder as well.)

If the cat is fine, and you either don't want to spend the money on a post cat 02, or, if replacing the sensor doesn't solve the issue, go back to where you got you sensor from (if you bought one, most auto parts stores will have the non-foulers) and pick up TWO of the non-foulers. Put one in a vice, and drill all the way thru it with a half inch drill bit. Screw the non-drilled one into the hole for the O2 sensor, screw the one you drilled out into that one, and finally, screw the O2 sensor into THAT one..... Idea here is to sheild the sensor from the full flow of the exhaust, and it 'fools' the PCM into thinking the cat is doing just fine. Even if you don't have one.

 

ya some people say the 94000 will throw codes sometimes. but i knpow i got used to my exhaust and wanted it louder lol

 

hey thanks for the info, a little confused bout the drilling one and screwing it into the other one....then u said screwing another one into that one? so 3 all together?? and if it runs better after i unplug the front o2 sensor, then that means my cat is bad or the sensor is bad, or either/or/and? lol t