The CEL was giving me code 41, so I tested and replaced the O2 sensor in the exhaust manifold. Prior to the code 41 issue, I started noticed a loss of power and really rough idle. Initially, I thought it might be a timing issue or fouled plug because the ride was so rough and jerky, but there was no pattern.

The threads in the manifold were so messed up that I had to replace the exhaust manifold. I drove it for a week with the O2 sensor out. With the O2 sensor out, I could hear a lot of back pressure. At lunch today, it got worse. Now it feels extremely sluggish and jerky, almost like there’s a sock in the tailpipe. It’s also now accompanied by an occasional backfire.

The CEL went off for a little while, but comes back on intermittently. I haven't had a chance to check the code yet. I also replaced the muffler 2 yrs ago. Could it possibly be a clogged catalytic converter?? Is there any way to test it, or anything else I should look for??

 

With the O2 sensor out, you "hear a lot of back pressure"? How do you hear that? What does it sound like?

The best check for a clogged cat is to remove the cat & look through the monolith to check the little tiny holes are open.

 

It's hard to explain, but it was kinda like a pop, or a sputter and then a pop... almost a backfire. It wasn't a loud, but I heard it when it started to jerk. It's hard to accurately describe 'cause I've never heard or felt anything like it. I wish I could be more helpful. With the O2 sensor back in, I don't hear it, but it feels the same... sluggish and jerky. I heard the backfire thru the tailpipe at lunch. It wasn't loud either, but was definitely there.

 

Of course, with the oxygen sensor removed, wouldn't the exhaust gases vent thru the sensor porthole, possibly making the idle smoother?

 

That's part of what I was wondering... whether you had plugged the hole where the sensor was. You need to plug that. At different RPM it can blow exhaust out or it can suck air in. Neither one is good and would not make it smoother.

 

They made a back pressure gauge/tester for testing clogged Cat.

 

I'll check on the back pressure gauge/tester. Any idea how much one runs, or if you can get one at Autozone or Advance?

Thanks for the clarification, Jim. I wasn't sure about that. If worse comes to worse, I'll pull the cat and check it out like you said. Also, I have a new O2 sensor in there now, but the CEL light still comes on intermittently. I'll check the code tomorrow, if I get home in time. It's still riding really rough. If I gun it, it'll pick up. But when I level off or accelerate @ a slower pace, it bogs down. Any other ideas?

 

See if you can rent or borrow one. Should look like this http://cgi.ebay.com/Tool-Aid-Exhaust...item5191217efe

 

AutoZone does have them for rent..after your done with it , you get your money back...

Of course you do know that it's illeagle to operate a vehicle with out a cat converter anyways..and a might stiff fine it will be..

 

before you jump into anything chk the code and post it here.........
also, you can just disconnect the frt pipe from the cat and just let in hang ( 3 14 mm nuts ) see it that makes a difference and while disconnected you can look inside the cat to see if it is plugged .........but FIRST ,,lets see what the code is ..