Driving last night, and got a CEL, Im used to getting one occasionally a flashing one, and it goes away, but this time it was solid and stayed went to buy a code reader, get a P0420 Code, and then the car started sounding different, and over the next few hours the sound got dirtier, a little louder not as refined and toned, sounded deeper and just worse. Started comparing to videos of how it sounded a few weeks prior, and totally different, and once you get into higher RPM it sounds almost like V-tec if anyone here has ever owned a Honda, also it shot a few flames(yes i didn't believe it either until I saw it myself) , which is cool but I can't imagine is good for the car. Its also sounding like stuff is coming out of the exhaust when its doing the overrun, like a metallic sound, has anyone else experienced this? is something else possibly wrong. If anyone wants to here the car their is a video of how it sounded a few weeks back and how it did yesterday, Stormtrooper_ftype on IG. Really starting to think that my Cats have blown out. taking it in for service Monday

 

A solid CEL is usually nothing to really worry about and is nearly always an "O2 sensor out of range" thing.
But a flashing CEL is a different thing and is meant to signify "major engine problem stop driving at once".
This is what my Owner's Handbook says:
"ENGINE/TRANSMISSION (AMBER)
Illuminates briefly, as a bulb check,
when the ignition is switched on. If
the lamp illuminates when the
engine is running, there is an
emissions-related fault with the
engine or transmission. The vehicle
can be driven but may enter
Limp-home mode with the
possibility of reduced performance.
Seek qualified assistance as soon as
possible.
If the warning lamp flashes while the engine is
running, reduce speed and seek qualified
assistance urgently."

 

I've had exactly same issue. The car started sounding significantly lower pitch than normal and above 5k-ish rpm different sound (exactly same symptom). I took the car to the dealer and they found the cats in pieces. Simply replaced the catalytic convertor and the car drives exactly same as before.

 

According to my dealer my exhaust valve was stuck and for the second time in month they are replacing the catback, I just don't think thats right, it doesn't make sense that a stuck valve would lead to a misfire, such a radical change in exhaust note, and loss of power, but I guess when I get the car back we'll see, Hopefully its fixed.

 

Damage to catalytic converter is a symptom of an engine problem. Insist any repair must also determine and address the issue that caused this before warranty runs out. Tell your dealer that you will call JLR to discuss this if they don't convince you they also fixed the underlying issues.

Valves don't get stuck, you likely have a deeper problem, likely injector failure. This has to be fixed or you will keep going through this AND unless this is fixed your car will take huge value hit out of warranty as nobody would want to take this project on out of pocket and pay market value for it.

 

I assumed this started from a misfire but in an email from my service advisor a stuck exhaust valve is the cause of the misfire and all my other symptoms, I'm no mechanic but I don't understand how that would happen, the car is a CPO, and its under warranty until late 2021, but thats not really a concern, Im more upset that in the month or so I've had this car, it's already been in the shop over two weeks

 

I have 7000 miles on my 16 F Type R and just before new years I got a CE light for a faulty Cat. Luckily I had my annual service scheduled right after new years so they got it fixed before I noticed any symptoms.

 

What have they done to fix stuck valve? If just chemical treatment then you will be back to the same issue shortly.

This matches my ownership experiences and was like that every year since new. Hope it isn't your only car.

 

 

It was the exhaust valve, not the valve springs, they replaced the whole catback exhaust, cats 02 sensors, and injectors.

 

Valve is part of cylinder head, if it was sticking and " they replaced the whole catback exhaust, cats 02 sensors, and injectors. " then it is very very likely still sticking. Sometimes valves sticking from carbon build up, and you can clean them without disassembly, but you need to take exhaust off to do so. Have they at least done this? However, most of the time to fix sticking valve you have to remove head, remove valve, and at the very least lap this valve (e.g. valve job).

Ask your dealer why valve job wasn't done if they diagnosed sticking valve, and get that answer in writing. You might needs this for when your car is out of warranty.

TL;DR There is a quick and insufficient way of fixing stuck valve, and sounds like that what was done.

 

 

Thats what I meant, the valves in the active exhaust, in the muffler, not the actual exhaust valve in the motor, Im just used to calling it that.

 

Those valves stuck open or closed will have zero impact on cataclysmic converter life.

 

Yep, that sounds just like what the OP has, a cataclysmic converter!

 

Rim shot! I wanted to comment but thought better of it since I'm probably already perceived as a grouchy contrarian (if that isn't redundant.)

 

Exactly, so the question remains what caused original converter to melt? Well, dumping fuel would do that, but how did it get there?

 

The valve had nothing to do with the Cat, it was just another issue, and still have no answer as to what caused the cat to melt, dealer doesn't know, picking up the car tmmr.

 

Not a typo: In 1975, their introduction was truly cataclysmic. It resulted in a Ford 302 Windsor that put out a whopping 122hp, driving the Mustang II to an asphalt blistering 0-60 in 10.2 seconds. I've been referring to them that way ever since.

 

Remember the slogan in the ads? "Mustang II, Boredom Zero."