2013,5.0

So my car is Making a funny noise and idk what it is. From a cold start it would start making the noise between 1000 and 2000 rpm but when it got warm the noise would go away. And at the time I had a SCT 93 octane tune on it. Well I took it off and the noise was still there and it sounded like it was coming from behind the motor somewhere around the flywheel. I drove it around like and decided to put a thicker wheight oil in it so I put 10w30 royal purple. It's allways ran 5w20 royal purple. I also put the tune back on it. Now the noise really comes in if I drive it cold. It sounds exactly like a rod but way quieter and it goes away when it gets warm I'm not throwing any codes and my oil pressure is normal. Can anyone help??
2013 mustang gt with 69000 miles