After my 2000 xk8 is warmed up I have noticed a "ticking" sound. This occurs when the car is setting at idle and I rev it up. As the car comes back to idle there are 2 to 3 "ticks" then at idle the there is no noise. It sounds like having a sticky hydraulic lifter in say a OHV Chevy V8. The engine runs fine and the noise only occurs when going to idle. I think it is the VVT system resetting. The engine oil is clean but I don't drive the car often. I am using conventional 5-30 oil.

 

I had a sound like this, turned out to be a cracked egr pipe.

 

Hi,

i've had that EGR pipe issue too, but the ticking noise occurs while warming up, not after that.
It is astonishing but the AJ26 -34 (4.0 and 4.2) are not equipped with hydraulic valve lifters, therefore i would have checked the valve clearance regarding ticking noises.

Fritz