Has anyone ever had a problem with a custom exhaust totally screwing up their engine?

I bought my C230 used and the previous owner had a custom exhaust put on. Now I have, maybe 12 faults showing up.

My mechanic says he doesn't even know where to begin.

Should I just have him do the repairs, clear the faults and trade in on a (gasp) Kia?

 

if he disabled or removed one of the oxgen sensors, that could throw a bunch of codes.

 

The O2 sensors are all still there.

You say the exhaust wil not cause any harm. Can you provide an explanation as to why

My mechanic is an honest guy. He knows his stuff and won't just say things to get $$$, so I believe what he claims

I can put the original exhaust back on.

What about installing the inline chip thing that increaes engine perfomance. Can that be causing any faults?

 

if your mechanic cannot read the codes to determine why the codes are being thrown, get another mechanic. there is no code that says "custom exhaust." the codes are very specific (tells you which sensor is reading abnormally, too high/too low, etc.). no idea what inline chip thing is. sounds like something on ebay that adds 0 bhp. chips really haven't been used since the 80s.