I've been having nothing but trouble with my 2004 XJR for the last couple of months. First, it died about a block from home, then restarted and made it the rest of the way, barely running, and quit completely. I had only about 5 psi on the fuel rail, so I started with a filter and fuel rail pressure sensor, then finally replaced both fuel pumps. The actual electric pump cross-referenced to Ford and BMW pumps and came in a Pierburg box like the originals for $122 each. The car then cranked right up and drove fine for a week.

Then I started getting codes for misfire on #7 on the way to work. On the way home it added #2. I parked it and ordered 8 coils (Spectra Premium) and plugs. I changed them last night. The car ran on 6 cylinders pulling it into my garage, but ran smooth and fine after the change. Going to work this morning I made a full throttle run through first and second and it was fine. Coming home I pulled out to pass someone and after five seconds of full throttle it stumbled and the CEL flashed. It ran home running a little rough, and on the way Torque read misfires on 2,4,6,and 8, along with P1314.

The only other problem has been with codes for the O2 heaters. I changed all four sensors last winter with Denso replacements and had a code for the heated O2 sensor ever since. I checked as far as the fuses and stopped, but I've since learned that a relay powers the fuses so I need to check that. I don't know if that's related.

I've searched and can't find anything related to P1314 that sounds like my problem. Any ideas?

 

5 seconds at WOT ! Is the fuel pressure holding up during that?

https://www.autocodes.com/p1314_jaguar.html

 

I guess I could hook up the gauge where I could see it, but the problem now seems to be only bank two.

 

Flashing MIL = severe misfires doing cat damage. Don't keep doing that or you'll be buying at least one cat!

Have you at least checked fuel trims??? Must be a zillion threads about those codes, misfires, fuel trims etc.