My son was driving my 2015 XF 3.0 after putting half a tank of 93 octane gas. He drove into a heavy rain and upon slowing down, the car began to run very badly. Took it to a shop in Weston, FL near Ft Lauderdale where they pulled codes for misfires on 5 and 6 and cat converter misfire. They suggested replacing all coils, plugs, and injectors. Seems extreme and the prices they quoted for coils and injectors were crazy. I suggested that they need to make sure the gas isnt bad before they do any repairs. I'm thinking of taking it to a Jaguar indie in Davey Florida. Any suggestions on what to do here?
THANKS

 

What DTCs were stored? P0305 and P0306? How many kilometres/miles are showing on the instrument cluster?

The Technician working of the vehicle should check for water around the cylinder heads.

 

Thanks for getting back to me!
Yes, P305, 306, and 1315, intermittent.

 

About 82,000 miles

 

Sounds about right?
I would recommend to replace all the injectors since you have miss fires on both banks. You can try different gas but it's doubtful that will do anything.
Is the car putting white smoke out one or both tail pipes? Also research and be aware of the HUGE amount of counterfeit injectors out there. I got caught and spent a miserable 2 weeks fighting the car because of bad parts that I thought were new!

Plug's and coils are a secondary possibility and I went ahead and put in new plugs but not coils when I did mine. Up to you.

Be careful as you also have P1315. It's a bad one.
P1315-00 - Persistent Misfire - Catalyst Damage. You don't want to keep driving the car because after a short while the cat will be ruined and they are $2400 EACH from Jaguar. Consider flat bedding the car to what ever shop you take it to.

Taking an old Jaguar to a dealer will be very expensive IF they will even work on the car. We have been told by several people they have been turned away if the car is 10 or more years old. Best to call first to see what the dealer says.

Thanks for posting the actual codes. We are working blind so much of the time as people just won't read the codes and start throwing parts at the car (Also know as loading the parts cannon!). Be sure and clear codes as your working so you can see what's current on your car. Don't want to be looking at historic codes.
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Heavy rain sounds like a clue to me, maybe the engine ingested some water????

 

Check if the airfilters are wet. (wet filters do not past much air....)
And yes: P1315-00 is serious. This can mean that lot of unburned fuel go to the exhaust and this will ignite on catalysators overheating them.

 

As others have mentioned, DO NOT operate the vehicle under conditions that cause the MIL to flash as catalyst damage is occurring.

 

There could be a simple solution which I'd check first. Plugs are so reliable with big sparks these days that people ignore them, so check your plug gasps first. Agree with everyone about killing the CAT, but so simple and cheap to check gaps!! Wide gaps also kill coil packs!!