Yesterday driving home it was clear there was a miss and a rough idle, then it set the MIL. When I got home the codes showed:

P0305 - Cylinder 5 Misfire
P0205 - Injector 5 Injector Circuit
P1316 - Misfire Excessive Emission

I pulled the LHD driver's side coil cover, and the coil nearest the cam sprockets should be cylinder 5 for this. A few months back I replaced the cam cover gaskets (including spark plug tube seals) with the Felpro Lincoln LS gaskets. I also did all 8 coils, and replaced the coil covers (yay steaming coils from a crappy seal). I took a good coil off of my XJR and swapped it in, and nope, same issue (but I'm going to swap it around to another cylinder to see what's up). While it was off I checked the spark plug and it looks pretty darn nice, and was at proper gap.

Both the coil and injector connectors looked clean (and i then sprayed with contact cleaner) and were seated well. After reconnection, code clearing, hard reset and restart, all 3 codes reoccured within about 5 minutes.

Tonight I am going to check resistance in the injector, check voltage to the injector, continuity from ecm to injector; and then will also be looking at same items for the coil. If all that checks out, I'm going to do a compression test; the oil and coolant look great; I guess puel the fuel pump fuses and it's compression test time. I'm running the trouble chart for P1316 (I know this is for an X-Type, I'm at work and don't have JTIS):



Prior to yesterday, it has been running stellar. I did change the tensioners 5 years ago with the 3rd gen metal bodied units, and when I have the cam covers off, I took a look around with my fancy new $20 USB boroscope camera, and things looked pretty darn good, so I doubt it's a jumped tooth.

I'm posting my odyssey on this. Any suggestions or colloquial knowledge is definitely appreciated though!

 

The culprit appears to be the injector. Luckily this one is accessible with the supercharger on, and I already have it pulled and another on order.

I measured the mirror image injector on the other side of the engine via the same tests to make sure the bad part wasn't me, and it passed with flying colors. So I'm cautiously optimistic.I'll report back Tuesday or Wednesday when the new part arrives and I put it in.

 

Last night I replaced the injector (RockAuto has a rebuilt one for $28+$10core+$3ship=$41), and it worked great! I lost the injector retainer clip into the area below the rail and is now hard to find. Since last night I tore into my XJR and pulled the supercharger, I stole one of these clips and it worked great. The stupid clip costs $27 and I just bought one.

This was easy!!! Issue resolved.

 

Maybe your boroscope can find that clip that decide to fly away....

 

Wow, this seems like a nice case of how this is supposed to work: Something is wrong with the car, you get codes that point you in the right direction, you apply your intelligence to filter out the noise (in this case, an argument of symmetry), then you order and install a replacement part. Nice work! Thanks for sharing.

 

I broke the snap that the injector plug uses to go onto the injector. I just pushed it down and snug, 6 months later no issues with it backing off.

 

I can see it but can't get anything in there lol. I'll have it back when I rebuild the supercharger on this car. I am currently doing so on my XJR:

https://www.jaguarforums.com/forum/x...ebuild-161450/

I mean this little guy (#4):



without it on, the injector will pop straight off the rail. I pressurized the rail with the key and priming, and forgot the clip. The injector loudly popped up and actually out of the hole and sprayed some gas around (luckily cold car). The little wiring clip that you're talking about I've done a dab of glue to fix on my Audi's before (VW makes garbage plastic and overly complex connectors).