Yeh, knew that a new CPS cured the problem. I was just trying to summarise the wisdom on general misfiring, which according to Andy S., "XJRengineer", is quite common in the AJI6 engine. He pointed out much earlier in this forum that the AJI6 engine is very sensitive to the choice of spark plugs, and thus advised folks to stick with factory recommended plugs, i.e. Champion RC12YCC (now replaced by RC12YC; the handbook originally said RC9YCC but Jaguar later recommended a hotter plug, see Jaguar TSB 05-1-07 [where EBC8143 is Champion RC12YCC]. There must have been a lot engine running issues forcing Jaguar to issue a TSB about it. Anyway, some folks in this and the UK forum do find NGK [[color=#222222]BCPR6ES for NA X300, BCPR6EIX-11 for XJR] a good alternative.

 

I had trouble finding the spark plugs (RC12YC) in the great white north, and eventually found them on line. As you can see they are titled as Lawn mower type spark plugs by most vendors.

 

I tend to think of the AJ16 as more of a tractor engine than a lawn mower engine! It's a workhorse. But it does sound a lot better than a tractor... It is a great sounding engine. Just the right amount of roar. I actually miss that quality since I haven't had one around for a while. The V12 engine sounds nice too, but is quieter.

 

I have 3 old x300's... I have never replaced a crank position sensor. I'm going to buy three right now to have on hand!!! thanks for the posts!