The first thing I did on my 98 XJ8L was to replace the chains, tensioners, waterpump, spark plugs and refresh all fluids. A tick still remained that went away when driving only to return with each start up. Perhaps a shim was needed..my mechanic listened and number three seemed the one. But when he went in it was fine. He wanted to say a cam or crank sensor, however the car runs beautifully with no symptoms..just the tick at start up. Research on my part says possibly variable valve timing unit..but I dont know anything about them to say so. Can someone explain how they work..or give me another idea..thoughts appreciated.

 

Most likely fuel injector: add some fuel system cleaner and see if that helps. And enjoy driving it if it is running well.

 

I have seen residue left on plugs from most of them..do you have a favorite to suggest? And yes...7,000mi of pure enjoyment so far with a 2500mi trip coming soon...

 

BG 44; Sea Foam; Gumout's most expensive

 

+1 for BG44 !