Jen K

My 2007 GL450 has started to sputter or idle rough. It almost sounds like it is going to stall.
I bought it in November 2016 from a non MB dealer. I have had the intake manifold, catalytic converter replaced and transmission serviced in Dec 2016.
The check engine light came on and now this. Any thoughts on what could be wrong?
Thank you.

mefferso

Rough running could be vacuum, ignition, etc related. Get the fault codes that caused the the check engine light to come on. That'll be your best starting point.

BlownV8

Mine was a bad magnet on the camshaft sensor. Take it in to a reputable shop and have it read.

Jen K

I took my GL450 into a local MB dealership. They did a diagnostic and turns out my catalytic converter is bad and O2 sensors. Which pisses me off because I have paperwork from the non MB dealership where I bought my car from, stating they replaced both of those in December.
My question is this, since my GL450 is originally from CA and has CA emissions. Do you think the dealership didn't configure it to those CA emissions standards? I live in Utah and am the 3rd owner. Do you think they put the wrong cats in?
I have reached out to the dealership no answer yet from them. I have also contacted Utah Department of Motor Vehicles to investigate and Utah Department of Consumer protection.
Does anyone have a good attorney? I was told by DMV I might have to file a civil suit if the dealership doesn't fix the issue.