The diagnosis of a faulty cat came from the dealer.Could be anything, but closed loop emissions components, exhaust sensors, hoses and engine breathing are a good start.
You can do a lot more learning how to use decent diagnostics to make measurements, rather than just expect a binary fault code result? The CAT is more than a box cleaning up emissions. It has sensors fitted that feed back corrections to ECU mapping.
They probably have more expert knowledge than you do so why not get it put right?The diagnosis of a faulty cat came from the dealer.
It may very well be the cat that is causing the rough idle. My cat has been throwing random codes for 3 years and this could be the progression of the cat getting worse. I was just wondering if it could be something else. I have limited money to put in this car. The car has 116K miles and has never had the timing chain and tensioner changed. It's just which repair takes priority.They probably have more expert knowledge than you do so why not get it put right?
Just because the car appears to drive o.k and not idle well doesn't mean your problem isn't CAT related? In U.K as part of the annual emissions test, they stick a test probe up the exhaust. If measured emissions are outside legal limits, it fails and can't be driven on the road.