Sulfur Smell/Rough Idle

Morning all,

I own a 1996 Buick Regal with 132k miles on it, 3.1L six cylinder.

The other day I was doing some general maintenance and noticed that the exhaust smelled like sulfur (rotten eggs). Now, I am loosely familiar with the causes of such a thing but not well enough to diagnose it properly the first time. The car has been idling rough since I got it (almost a year ago now), I have a feeling that it could be the O2 sensor causing the rough idle and the sulfur smell but I am not completely sure.

Thoughts? Does anybody think I should have one of those fancy three-part injector cleaners done?

Rotten Egg smell usually means catalytic converter or O2 sensor.

Engine light on???

No, the engine light is not on, sorry forgot to mention that. I really have a feeling that it might be broken though. The car is really in great shape, but it just seems strange that the light is not on… Do check engine lights ever break…? Idk.

The check engine light is just a bulb - so of course it breaks. Its also just got wires that carry electricity to the bulb, so that can go wrong too.

The check engine light should turn on everytime you turn the key and all of those other dash lights come on. Either way have the car scanned for error codes - many auto parts stores read them for free.

Thanks for the help bub. Good thing I came to this forum…

I am going to replacing the up-stream 02 sensor. If somebody thinks that is not the problem then say something. I suppose I should do the down-stream sensor as well.

I don’t know if it’s the problem. I’d first try to read any error codes that might have been generated.

Hey bub (?) - do not just start replacing parts. Get the car onto a scanner to check for error codes. That alone may tell you what you need to know or at least give more clues.

Ideally you would have a scantool that can read realtime data from the PCM including the O2 sensor outputs. You can buy entry level versions of these for probably less $$ than you’ll spend randomly replacing parts.