2003 Jaguar XK8 with ticking noise at driver's side door/dash area. The ticking noise is fairly fast and steady roughly 5-6 times per second. The frequency does not increase with increasing rpm or road speed. If I shift into neutral and rev to 1500-2000 rpm, it goes away, but returns when rpm comes back down to driving speed. This has happened twice this week on the drive in to work (temperatures in the high 20's to low 30's), and roughly four miles into my commute. No noise was noted on the drive home (temps in mid to upper 30's).
Today, when I got to the parking lot, it was still ticking away, so I had a chance to listen around the open engine compartment. I couldn't hear anything from the top, but definitely heard the sounds from under the driver's side firewall. First thought would be an exhaust leak - but it doesn't change frequency with changing rpm.
I did hear some ticking last winter, but much fainter. It only did it a few times and then stopped, so I never was able to trace it. Any thoughts? Relay chatter? Thanks!