the problem #2 listed in my first post is becoming one of those almost every time things. If i drive about 75% throttle up the hills it is not to bad however i found that goung up with little to no throttle % then increasing slowly it began to shuttler again Do you think this is a symptom of the coils, I am nervous about gearbox problems after doing some reading on the net. I thought gearbox problems would be the last thing i would have with the jag, it is so smooth....
I am 90% confident that it's a coil problem (leaking boss seals, or even water in spark plug chamber(s)). You can easily remove 3 ignition coils and spark plugs on the left side (from the driver position, non-UK). Probably takes a 15 to 20 minutes of easy and pleasant work, unless you have a cold weather and no garage.
After coils are removed - see if there is any moisture or oil present. Remove spark plugs and check if they are OK and not cracked, damaged or burned out.. etc. Do you have any smoke coming out from rear left or right side when the engine is not working normally ?
Gearbox problems are - jerking, shuddering, bad noise, delayed engages, not normal gear changing etc... I am not sure it's a gearbox problem.
If you are able to scan your ECU at the dealer - go for it, because each ignition coil costs around 40-50$ in USA and you will need 3 to replace that are under the intake manifold unless you know the failed coil by error code. With other 3 coils you can play around later, again if you have read ECU error codes, you will know which one really failed. If you need to drive 500+ km it's not worth it and I would order some spare ignition coils - gas is expensive nowadays.
To be honest, If you are unable to read with the ECU reader, buy 3 ignition coils (for cylinders that are under intake manifold and hard to access), 2 boss seals (10$ each or something), lower breather elbow (around 10$ or something, L - shape, but bigger than upper breather elbow you can easily access - actually this was a recall and done at no charge with Jaguar (the upper breather elbow)). And perhaps 6 new spark plugs that you can change. Those run from $2-20 a piece, with iridium and platinum on the expensive side.
I am doing such repairs myself and replacing ignition coils, spark plugs, lower breather elbow, boss seals, (valve cover seals are always OK, make sure you use some special seal lube/silicone, it should be used a bit there - you will see where the old silicone was used - preferable buy it in black color - costs around $2-$3 one tube). I am usually in no rush, this job takes ~3 hours. It's very easy actually and first time it will take a bit longer of course. You can also get inlet manifold upper/lower gasket (2 + 2 required), cost around $10 each, but they are OK usually.
However, I am not doing a full coolant drain - I raise one of the coolant pipes (open the cap of coolant expansion tank before removing the pipe to intake manifold). You will just need to make sure there is no air in the coolant pipes - there is a small plastic piece what you can use to release the air from the system.
I hope this helps you a bit and also any other Jaguar S Type owner.
