It doesn't smell like sulfur at all. I do think they are original though. Are the passanger side cats always welded on both sides? I couldn't pull it down and bust the **** out of it because of that. My LT1 car wasn't like that. It was bolted on one side and welded on the other. We'll know tomorrow. I'll post back tomorrow night. Thanks guys.

Benji

 

Pull the injectors and see if the tops are full of trash above the screen. There is a hole about 3/8" deep before the screen. If ya can't see the screen they are stopped up,but it should throw a code.Fuel filter also.

 

Replace O2 sensors (fronts with new ones, rears with simulators or tune them out) replace cats with straight pipe. Gain torque, hp and no SES codes with either simulators or having them tuned out.

 

my left cat went bad at 40k... so i guess maybe yours are over due too... might as well take them out...

 

my left cat went bad at 40k... so i guess maybe yours are over due too... might as well take them out...

 

For you bad cat people. There is a federally mandated warranty on them for 8 yrs 80k miles.

 

i though it was 6 years 60k

 

nope, he is correct, 8 years, 80k miles. You can take it to a dealer and they will replace the bad one(s).

 

Not when the car has 102k on it.

 

She dropped it off an hour ago and the dealership is fixing it, for free (thank god). I'll let you guys know when she gets back this evening.

 

That's cool that they're fixing it, it really sucks to buy a nice car that's not right. When I bought mine it had some issues with an aftermarket security system that was only partially removed, and a bad opti. The car amazed me on the test drive, then it crapped out as soon as I got it home. It took about a month to get everything worked out. I guess that's just the risk of buying a great car with 100k(mine had 104k) rather than a ****ty new car. I hope everything gets taken care of, and congratulations to the new f-body owner.

A couple of things about the issue...
I wouldn't doubt that it could use new O2s, but all 4 of em throwing codes at the same time makes me think that's just the effect, the cause is elsewhere. This is just a blind guess but it kind of sounds like an internal leak in the fuel pressure regulator, gas leaks past the diaphragm and gets sucked in through the vaccum line. That would make it run very rich all of the time, the O2s are reading correctly but the PCM can't compensate for it so it spits out codes.

The cat(s) may also be restricted as a cause of this, they need the rich/lean cycling in order to burn everything. Also if it is restricted it should be getting very hot you can check difference in temp between the 2 that would tell you if ones clogged. Before you go gutting the cats with OBD2 you have to get simulated O2 sensors(just the 2 after the cats) or get them programmed out, or the PCM will throw codes. I hate to say it but you also might want to consider how much louder it will get, especially if it's a womans car.

In any case I would just do ALL of the maintenance/tune-up items, if for nothing else just to know that they were done and when. If the dealer didn't put in new O2s I'd seafoam it once, then replace the sensors afterwards. Maybe even remove and clean out the TB and all it's little passages, EGR too if LS1s have one. Definitely flush the trans/cooler and the replace filter, I'd add an auxiliary trans cooler too ASAP, that's speaking from experience. And after all that she'll really owe you. GL let us know what the dealer found.

 

He knocked the cats out for her and it runs a ton better. I guess that was the problem. I appreciate all of your guys' help. And about it being loud and a womans car, she couldn't have it loud enough. She loved my car when I had it open long tubes. She wants hers to sound like mine, so a cam may be on order here soon. Thanks again guys.

 

something that will only take a few minutes: clean the MAF off. The wires on mine were caked in crap and i had problems with my powerband cutting out around 2500-3500. It wasnt as dramatic as your problem sounds, but after i cleaned it all out, my power problem was gone. I'm not saying thats the fix, but it will probably help!

 

LS1s don't have that type of pressure regulator. They, with the exception of 97 'vettes, have a returnless fuel system.