Rough Idel!

Love The Site!

Today while I was on the interstate my Service Engin Soon Light came on. I live about 45 minutes from where I was going and my truck did fine. No SES light on the way. On the way back it came on so I stopped at a friends house turned my truck off and then back on and no light. Well about 10 minutes later light is back on and I notice a rough idel and what seems as a loud Cat converter. ** Something in my exhaust is making a noise** My engine seems like it wants to pull foward at a idel as well.
And when I opened my door it smell some kind of fume but its not gas.

Anybody shed some light on this please....

I have had my Converter worked on before and that is why I say the noise is the converter.

Please Help!

Go to Autozone for free and have them scan for the codes and come back here with them.

We need the actual codes.

When you say you had your cat "worked on", what did you mean by that?

Also, was the smell like rotten eggs?

No it's not rotten eggs. And when I go to Auto Zone I get a link error for some reason.

I had all the stuff inside of the converter knocked out cause it smelled like Rotten Eggs. But that was along time ago.

No it's not rotten eggs. And when I go to Auto Zone I get a link error for some reason.

I had all the stuff inside of the converter knocked out cause it smelled like Rotten Eggs. But that was along time ago.

That is probably your problem, you can't just knock out the cat innards and expect your engine not to notice it.

when i punch out the innerds of a cat on a 91 or older, nothin, but on any 92 to newer, boom ses is there within a day or two

when i punch out the innerds of a cat on a 91 or older, nothin, but on any 92 to newer, boom ses is there within a day or two

Anything with a O2 sensor after the cat will cause a problem.

1995+

i swear all f/s chevys 92 and newer that ive punched a cat from have put up the ses, but my 91 didnt, i know that in the 96 to current there is a post cat o2, but why the 92's did it is beyond me (only 3 of them, but all three threw a ses and i never did find out why) what i was saying is they did, but shouldnt of, only thing i can think of is lack of back pressure, and the other o2 reading that

i swear all f/s chevys 92 and newer that ive punched a cat from have put up the ses, but my 91 didnt, i know that in the 96 to current there is a post cat o2, but why the 92's did it is beyond me (only 3 of them, but all three threw a ses and i never did find out why) what i was saying is they did, but shouldnt of, only thing i can think of is lack of back pressure, and the other o2 reading that

If there is no O2 sensor after the cat, then there is NO way the computer can see if the cat is punched out or not.

1995 and later is when they introduced the post cat O2 sensor.

What could be causing my link error when they try to scan for codes?

And when my problems happens is when I drive for a long period of time. Never happens when I am going somewhere on a short drive just when I drive for maybe 45 minutes to a hour. This morning when turning on my truck my exhuast was still making the noise until I got about 2 minutes down the road then it stoppe and my SES light never came on. What do you think?

What should I do?

Could have been just their scan tool.

You need to reinstalla proper cat in place of the empty one you have there.

Do you have a CPI or TBI 4.3L?

CPI 4.3 Vortec

I talked to someone today and I explained my problem and he said that is does not sound like there is something wrong with my Cat converter. He said it sounded like to him that there was a valve that opens up after the engine gets so hot that is staying open. I want to say he called it like Pollution valve or something to that affect. He says that is opens and recycles what is not burnt through your engine and its not closing and cause thing rough idel. Has anybody ever heard of this?

Keep giving opioions I need all the help I can get.

Ah, the EGR valve.

Yea, I would remove it and clean it and reinstall it.

Or if it is cheap, just replace it.

This is what I did.. I took the EGR valve off and notice alot of carbon build up on the valve and inside off the motor. I cleaned them off and replaced the gasket in between the valve and the motor. And now it idels alot smoother. It also got rid of a discreet sound like a clicking noise. Is that related?? I am am going to get my Cat replaced sometime this week.

Did you spray it will TB cleaner to dissolve the carbon out of it?

Yes...

Is the clicking related?

Be more specific, clicking tells me nothing.

Does it click along with the engine?

clicking? chech your oil...

Yes, it does click along with the engine.

I didn't think about this but I do have a small oil leak and I did change my oil the other day so maybe that is what is it. Its very small click that gets faster as you accelerate but you cannot hear it all the time.

Is there any chance you could post up a small sound clip of this noise?

Could be an exhaust leak, but I would like to hear it.

I think that the clicking is to discreet to be recorded onto anything. I will try but I really doubt it.

More than likely it is an exhaust leak from the manifolds or the exhaust system itself.

What do you do to fix a leak from the manifold?

Install a new manifold if it is indeed the cause of the sound.

How difficult is that?

depends on your handiness.