Thread: Need advice on some codes & dealer recommendations

So, long story short I have a 08 GP GXP, I brought my car to the dealer to have some codes checked (Check engine light has been on for about 40k Miles) had a friend hook up his computer, and it stated something along the lines of bank 2 o2 sensor. Car has ran fine with the check engine light on. Dealer call's me and say's the Catalytic Converter needs to be replaced, can't just replace it, have to replace the whole exhaust system ($943.94) they also say it needs to have a Fuel Induction Service done due to code p0300 ($200.00 and another code P0420. They also want to replace the spark plugs and total for everything is $1741.44. I had some other minor work done while there, ABS sensor's and fix A/C. I tell them that I will hold off for now. Two days later, the car starts really acting up, sputtering, obvious signs of a misfire. I bring the car back to the dealer, and while it's there, a semi backs into it doing almost $6,000 damage. (really pissed me off, the car was spotless, never any bodywork, in nearly mint condition)

Would it be best to go ahead and replace the OEM exhaust/Cat or for nearly the same price, go with a aftermarket such as magnaflow, borla, or something similar. Do these codes necessarily mean I need to replace the exhaust?? I was just transferred to this area for work, and after the things that have happen so far at this dealer, I'm having a real hard time trusting them.

thanks for any input

your rear o2 went bad, over fueled the engine, and clogged the cat on you.

find a local muffler shop get a new cat installed. and a new o2 sensor if your not up to the job yourself.

sucks your car got hit, but that should be covered.

I'd replace the spark plugs yourself, they arent super hard and that will most likely fix the P0300 code.

The P0420 is the converter going bad and you can just replace the converter section, you should not have to replace the whole exhaust system as that is just crazy talk. I am not sure if AC Delco sells just the downpipe section without the catback. On a 3800, you can just buy the downpipe with cat converter.

Thanks guys, and yes the dealer is fixing the damage, and they gave me a free rental.

I'll try to call around to other muffler shops locally and check

maybe I should clarify a little more. The dealer said that GM does not sell the just the Cat alone, to replace the cat, you have to replace the whole exhaust system if you want a OEM cat.

thats a crock of sh it. they sell just a down pipe with cat. why do you think it unbolts from the cat back and the rear manifold?

dealerships are thieves dont ya know.

that's kind of what I figure, that's why i'm here asking the pro's!

just hit a local muffer shop or two, ask for a est for a stock replacement cat. you need a real cat, do not let them talk you into a high flow one. or you'll have the p0420 code come back from the cat.

You need one of these things, not the entire exhaust system.
http://zzperformance.com/3800/exhaus...-downpipe.html
http://www.amazon.com/Eastern-Manufa.../dp/B000Q0RXYK