Pulse/tick from engine compartment

Hello everyone,
I have a 97 xj with the 4.0, aw4 auto, selec trac NP242, dana 30 front, Chrysler 8.25 rear. For many years now, it's been making a tick or a pulse noise from the engine compartment only at around 1700-2000 rpm. The oil pressure is good (37-50 from oil sending unit, mechanical gauge shows a little more). we've had this jeep since 99, and have always changed the oil every 6 months, although now we've been doing 3mo./3000 miles. we've always used Valvoline conventional 10W-30 and for about a year and a half, a mopar filter. There is no performance difference in those rpms, and its not very loud, music or windows down blocks it out. Is this normal and is it detrimental to the engine?
Thanks for everyone's help!

Could be the evaporative air purge solenoid. They have been known to sound like a clock. The best clue for this is that the frequency of the tick does not change with engine speed.

Thanks for the reply,
I believe it does change speed a little as it goes through the rpms, only slightly, also, it only does it when its warm and has been ran for a little bit.
Thanks

Could be an exhaust leak. That's what I'm fixing right now.

I'll definitely look into those, the system is getting pretty old it makes sense though. I've always been curious since it didn't make that noise at idle so that might be the problem
Thanks!