I just recently purchased a 2002 (M25034) S Type. Ran fine for first week - then popped a P304 + P420 code. I inspected bank 4 coil & swapped with the bank 5 coil. Issue went away - till this week. Driving to & from work I noticed hesitation & decay of acceleration intermittently- not as noticeable as a rock or hitch in momentum but still noticeable decline or delay in smooth acceleration. Then the P405 & P455 codes came up. My first inclination was to change plugs & coil packs but thought it best to ask the Jag Forum Elders for advice! Bank 4 Misfire vs EGR??

Thanks in Advance!!

 

Is P0405 a typo? I'm not seeing anything with that code in the official Jaguar list:

http://www.jagrepair.com/images/Auto...tos/P20001.PDF

Did you mean P0305? You previously had P0304 and swapped coils between cylinders #4 and #5. If that coil was marginal and was acting up again, it would flag code P0305 for the new location at cylinder #5. If that's what you had, definitely change the coil.

Make sure you get a name brand coil, such as Motorcraft, Bosch, Denso, etc. Stay away from the no-name bargains on eBay. Same for the house brands at most discount part store chains.

I wouldn't worry about the P0455 code for now. That's a fault in the evap system, but typically won't affect drivability. This message often clears itself, too, if the gas cap had been loose.

 

That’s the weird part - it wasn’t a typo but maybe my scanner malfunctioned. Just ran out to double check & instead of P405 it is reading P305 only. So it did move with the coil from bank 4 to 5. Ordering a brand new coil & will see if that fixes the issue.