Thread: Clogged cat, bad o2?

Alright so a few days ago I noticed when driving the SE that it would get surges where the RPMS would bounce a bit, in motion and at idle. Turn the car off and then back on and it would releave it for a few miles. I got an SES light and 2 things came up

1. Multiple cylinder misfire
2. o2 bank 2 low voltage

When I got back to the house I erased the codes after checking wire connections and spark. Took it back out where the problem persisted. This time only getting one code

1. Cylinder 4 misfire.

This time I took the plug out and put in another that I had as a spare just to see if that really was the issue. Well sure enough the problem continues with the same code(s) coming up each time. I haven't seen the o2 code since that one time though, but is it a possibility that it is what's causing the issue? I mean with the tune it does run rich and would make sense if it went bad. Or maybe the cat? Has almost 300k miles on it and with it running rich since the swap maybe have done it in. I have spares of both things but don't want to bother if no one thinks that's the issue. Let me know what you guys think and i'll def look into it

a clogged cat would make the car feel like it has no power. if you got into the throttle it would feel like its bogging down.

if it can't exhale theres no where for the clean fuel and air to go though, sounds totally possible to me with 300k, mine was shot at 220k Theres only a few other things that can cause a random misfire and with a O2 issue on top of that, thats where i would start

Well a little more info on the problem, when you give it gas it studders, like little blurps of power... Best way I can describe it would be speed bumps

def sounds like cat, thats what mine did, almost feels like a REALLY out of place rev limiter, basically you have to hold it wide open and after awhile it MAY climb a little higher but probably not, if thats basically it i would start there!

Originally Posted by ninnyGTP

Well a little more info on the problem, when you give it gas it studders, like little blurps of power... Best way I can describe it would be speed bumps

Sounds a lot like a misfire. If cylinder 4 is the only one lighting up the screen, diagnose the cylinder only and not something that should cause misfires at all cylinders.

Plug
Wire
Wire not touching the O2 wiring
Coil pack tower clean?
Coil firing that cylinder?
Injector firing? Read the plug.

I'll check all connections and clean everything just to make sure. Get back to you with any updates