TJ engine knock

I've got an 03 TJ 6cy with 14K miles. Just started hearing some engine knock 3rd through 5th gears at 2200+ RPMs. Most ofter under load such as while going up hill. Oil pressure guage appears normal and unchanged. Oil level is in range.
The only engine mods. have been a K&M air filter and installing a Banks Cat Back exaust.
I'm stumped. Any thoughts as to what is causing anf how to fix 'knock'?

Is it a light pinging or a heavier knock?

How long has it been since you put in the K&N and exhaust?

Is it a light pinging or a heavier knock?

How long has it been since you put in the K&N and exhaust?

Its a light ping. Within 2K of K&N and muffler. Since my original post I filled up with premium and knock is gone---so fare, Not sure I'm ready to say I got a bad tank.
What's your thoughts?
Thanks for taking the time to respond. Thanks man!!!! :smokin:

Sounds like a little detonation with the regular gas.

Check the timing and plugs for carbon buildup. Could also be combustion chamber deposits that "glow" and cause the pre-ignition.

JD