I had irratic idle, sometimes to the point of dying, ck eng light, bas/esp light, and cruise control quit working. Replaced throttle position sensor, fixed all, cruise control even started working again.
For what it's worth, my Commander had a left rear rattle that was self induced. I replaced the rear shocks with gas shocks and didn't give the lt upper shock mount bolt quite enough torque. After retorque, no rattle.
After my 2"RC lift I had a rattle. But, I installed new rear shocks during the lift, gas shocks for my Jeep with a 2" lift. My rattle was in left rear, and was simply a top shock mount bolt needing a wee bit more torque. I really don't have a clunk, thank goodness.
Don't know if anyone has seen this yet, A stretched Wrangler gassing up in Detroit. It has a 3rd row seat. It is wearing a Manufacturers Plate, and has a AEV decal on the windshield. It is rumored to be called JK 6 pack. Cool or what?
Heat makes things expand, and cold makes them contract. It affects air molecules the same way. Nitrogen would stabilize the up and down swings. Usually I add regular air on the cool days, then leave it alone unless the temperature really spikes up to the mid summer range.