LS430Lexus

'02 GS300 w/ 75k. Just did the ball joints, rear struts and thermostat. Check engine light is on with a p0430 code. Lexus dealer says to replace exhaust manifold for $1850. An independent muffler shop saws they could not find an exhaust leak but I may seek another opinion. I have searched and found many references to this code that are caused by cracked hoses, bad o2 sensors and exhaust leaks.

Has anyone actually replaced the manifold and solved the problem? Also, suggestions for independent shops in the metro Detroit area are always appreciated. Thank you.

Ava92

iTrader: (3)

I bet it's an O2 sensor, or maybe a bad flange/gasket upstream of the O2 sensor

I had P0420 which was an O2 sensor
couple years later got P0430 which was from installing headers, didn't attach them 100% and had an exhaust leak lol

leaks are usually pretty easy to notice, it will smell/sound weird

badblackgs

iTrader: (1)

the exhaust manifold is made of a high quality stainless steel that is resistant to rust and corrosion and is not likely cracked like iron manifolds have a tendency to do. keep searching for a good shop that can tell you exactly whats wrong with the car. 1850 is alot to throw at a car that might not fix it.

CIGLexus

iTrader: (1)

Of course the dealer will say that, it's not their money. If in fact a manifold cat is bad (which is rare), there are plenty of used ones online for $100-200.

Mcon

iTrader: (1)

This is was my mid pipe with the small exhaust manifold clogged.



All the crap that have inside on the small exhaust.


I'll just express my experience with that code. The exhaust manifold maybe is fine, but the mid pipe having a small exhaust manifold also, that may not be covered for mileage, but by the years in which the car was almost unused and the moisture that enters through the mufflers creates the clogger on the small exhaust. Check your mid pipe, maybe is clogged. Good luck.

PandaGS300

Did you buy a new one or used one?

Mcon

iTrader: (1)

I buy a used one with very low miles.

Mcon

iTrader: (1)

Also, you can go to any muffler shop and tell to the guy to cut it and add a pipe. I see a few guy doing that. I personally like factory pipe. Cops here no play with muffler sounds. :-(

LS430Lexus

It appears it was the oxygen sensors. Replaced two (one upstream and one down) and driven about 125 miles over several trips. The light has stayed off. Too early to be 100% sure but so far, so good.