Jaguar 1997 XJ Executive wont start - please please help

[scottXJ]

I recently purchased a 1997 XJ Exec 3.2l, it starts intermittently (mostly with east start spray), initially burning very rich, flooding the cylinder and soaking the spark plugs on non start, has now started to burn lean and the spark plugs are dry on non start almost as if the injectors are not firing. I have checked the inertia switch but this appears to be in working order and checked for fault code no current codes 1 saved code p1621 cylinder circuit malfunction. The car had been lying idle for a month or so and was low on petrol too. I have taken it for a good few runs and it runs well. I have had a mechanic out a few times who gave me the above report