vetintheblood

So I was out for a short drive this weekend and for the last 1/2 mile before I got home, my car was running REALLY rough. I could definitely smell a rotten egg odor coming from the exhaust.

I'm guessing it's one or both of the catalytic converters.

Need some advice: I don't want to replace both of them if only one is bad. How can you tell which one is clogged? Can they be unclogged or gotta be replaced? Thanks in advance!

JR-01

You have to burn out the carbon in these cars once in awhile. Get the cats up to temp and drive it like it was meant to be driven.
Pull your codes. Maybe you have a bad sensor.

grantv

If one or both cats are actually done, you should be getting codes. P0420 (left/drivers) or P0421 (passenger side) are the codes IIRC. That is unless you've had the rear sensors opted out.

JR-01

Modern catalytic converters should last the life of the car unless you do a lot of idling or slow driving.

Fast Cop

You could have a bad 02 sensor, but if that were the case it would throw a code or 2. Pull codes and advise.

eevette2001

Lots of guys here have their old exhaust hanging around to sell, probably get a great deal on a used one.

Vetteman Jack

If your catalytic converters are bad, that would be a good cost effective option if you can get a low mileage stock exhaust complete with cats.

vetintheblood

Gotta admit I haven't had it over 100 for awhile

BTW, I was also getting the 'check engine' light. After pulling the codes I started the vette a ran it for about 5 minutes - runs OK but still getting the 'check engine' light.

Pulled the codes. There were 8 each for LDCM and RDCM - not listing those because I've been having door lock problems for awhile and I think that's unrelated.

Besides those here are the remaining codes:

10-PCM P0300 H C - Engine Misfire Detected
B0-RFA U1016 H - PCM loss of comm
B0-RFA U1064 H - BCM loss of comm
B0-RFA U1096 H - IPC loss of comm
B0-RFA U1255 H - Serial data line malfunction
B0-RFA C2105 H - Right front TPM sensor malfunction
99-HVAC B0367 - Right actuator feedback open

JR-01

Make sure your battery is 100% charged. Low voltage can cause a heck of a lot of problems with these cars.

vetintheblood

Just wanted to follow up on this - the symptoms were a 'check engine' light and the vette was running REALLY rough. I could definitely smell a rotten egg odor coming from the exhaust and I was concerned about having to replace one or both of the catalytic converters. All 8 spark plugs were replaced 6 months ago.

After getting a complete diagnosis it turns out that it had 2 bad spark plug wires (should have replaced them when the plugs were switched out ) and it had 3 bad ignition coils. So it was just dumping unburned fuel into the exhaust system - not good.

In the end with all new plugs, wire, and coils it runs like corvette should! Thanks to all for your advice

leadfoot4

grantv

Makes sense...
With this: "10-PCM P0300 H C - Engine Misfire Detected"
And this: "All 8 spark plugs were replaced 6 months ago." (no wires mentioned)
It makes sense that it was a wire(s). Old wires get brittle. Never mind the fact that if changing plugs, just pulling your wires might cause a break. Sorry I didn't see this part earlier, would have been my first guess with the 2 above put together.

JR-01

Why would cause the 3 coils to go bad?

Phanni

It's likely tied to the plug replacement.
I've rarely heard of the coils malfunctioning, but when you're in the area pulling the plug wires, something weird could have happened.

JR-01

.....or the dealer just piling on the parts and labor. I could see 1 coil going bad, but 3 at the same time?

Phanni