here we go. My new 2018 renegade with 3000 miles...2.4 multiair From the start the valve train was noisy, chalked it up to typical 4 cylinder behavior and I’ve since read that they are a little chattery. That’s fine BUT today i noticed it was making a louder noise when taking off from stops. I pulled into my driveway when I got home and left it idle in park while playing with the gas pedal. Idling sounded like it always had. With a light rev, it made the noise in question briefly on the way up. Just barely pressing the pedal and holding it resulted in the noise being constant. Loud, harsh rattling /knocking. The sound of excessive clearance and metal on metal. Under load it quiets down, at idle it quiets. There’s that narrow swath of rpms where the radial forces are neutral and whatever it is ( my guess, the cam) is free to chatter about in its excess space. Multiair uses some sort of hydraulic coupling between the cam and valves or lifters or whatever... so I think that’s the root of the issue. I checked the oil and it does seem a bit low. (I’ve read they tend to burn oil) Gonna let it sit until I buy a quart of oil for it and go from there. If it does not go away I’ll be taking it back to the dealer again. Again, I understand these engines are noisy but this noise is NEW and alarming.