Okay. Here is the latest plan on my 93 LT 1 with 17,000 miles. The car has been running bad off and on for a few years. The misfires, rough starts etc have damaged one of the cats. My cousin is a manager at my local chevy dealer. His shop has given me a reasonable estimate to replace plugs, wires and opti-spark. He has good vette techs. They recommend having the cat repaired before they begin diagnostics for any other problems before the plugs, wires and opti-spark are replaced. My guy doing the cat recommends gutting the original instead of replacing it now. He suggests replacing the cat after the car is fixed and running well. Do any of you think that a gutted cat will throw a code that could interfere with the Chevy shop's diagnostics? No check engine lights or anything come on. On another note, all my issues started when I hosed the engine off a few years ago, (like a dummy). I started and drove the car a couple days ago and it ran fine. When I got ready to start it to put it back in the garage, it wouldn't start well and idled fairly high and missed and jerked when putting it in the garage. Its a mystery, so any of you that have any other suggestions I would appreciate it. Also, this car has never been worked on except usual maintenance. I did have MAP and ICM replaced. Also, does the driver side cat have an oxygen sensor? Saddest part is it looks brand new. Thank you all for any advice.

 

I wouldn’t do anything to the catalytic converters. It should not be bad at 17,000 miles unless you were absolutely dumping fuel.


But if removed, the ECM is not going to care as there are no post at 02’s in 93.

 

Do not let them throw the old opti out. Keep it. The sensor is way better than anything out there today. If the shop really has vette mechanics, they would know this and would maybe say, " we should open up the opti and see what it looks like and maybe just clean it and replace the cap and rotor as your bearing is not worn out at 17K". Dan

 

Thanks. We know the cat is bad because of the noise and the small debris and flakes coming out the driver side exhaust. The sound is like the rattle of a snare drum. Its loudest at around 1900 RPMs. I fear that I could possibly have injector problems too that might have damaged that cat. I appreciate your input. Hopefully I can get this thing back to snuff. If you think of anything else you can advise me on would be great. These cars are definitely out of my league.

 

Thanks. I will remember that.

 

Diagnose your problem before throwing parts at it.

 

I just purchased magna flow cats for my 1993 (2) and there are 2 02 sensors one on each cat. I purchased the cats from Hot Exhaust took a while they were out of stock but finally got them. A lot less back pressure and free flowing than stock

 

Take the old cats to recycle shop I received $120 for both cats