I'm not sure on Jaguars, but in my experience, sensing rich, running lean to compensate, usually leads to a vacuum leak that won't set a code. Running a fuel trim map may help verify this, a basic obd dongle to a laptop. Or I may be in the stone age...

 

I have the dealer software. I will put it on the lift sometime this week. ill see what the computer says. ill also check the plugs and measure exhaust temps at that time. i hope i find the smoking gun

 

Let us know for sure, I'm sticking with an O2 only because a MAF would have both banks running lean, and I just can't see a whole bank of FI's clogged at the same time, and that heat sure as phuq isn't caused by one injector spraying weak, but I could be wrong on all counts.

 

Stone age thinking might be spot on

 

Sorry for not getting back to posting the results. I got stuck in Mexico for a few weeks.

Anyway, after a 45-minute drive, I measured the exhaust temps of the exhaust tips (107 & 110), and manifolds (355 & 350). Both sides were within 5-10 degrees of each other. The bumper felt cool tho the touch. I also did the OBD scan and it came back with no codes. I also pulled the spark plugs on the passenger side and they looked good.

 

That ground electrode looks like it has some white deposits on it. The only way to truly read EGT is to install a probe just past where the header collects the pipes into one, and then connect that to a guage you can read while driving.

 

I went back and looked at the pictures of the plugs and compared them to charts I found online. It's definitely running lean. Now it's got me wondering if it only happens when I'm at high speeds and it's a fuel delivery issue or if it's happening all the time due to a o2 issue. I might pull the plugs on the other side to check those as well. I hope I don't have to take it to a shop to fix this issue

 

Well, I decided to take the car to a shop to have some diagnosis done that I wasn't able to do. They were not able to find any issues and they think that it is a result of driving the car hard.

 

I call bogus on the "driving hard" response. Otherwise, there would be a fleet of us on the board with peeling paint. Assuming you've checked spacing, as mentioned above, I'd lean toward a factory paint defect. Repaint and move on.

 

My guess would be some object or substance that would ignite at the temperature of the exhaust tip.

 

Since the valance has already warped from heat damage, it'd be surprised if you didn't need to replace it. That being said, I would look at lowering the exhaust a little. Doesn't need to be a lot, but about an inch would likely give you enough clearance from the valance where the heat won't be an issue.