2012 Jeep Grand Cherokee pinging sound

jeep
grand-cherokee

#1

Engine has a pinging sound like maybe a lifter. It gets faster as the engine revs up. The engine has fresh synthetic oil. I have been told to let the fresh oil work out the pinging, but it doesn’t seem to be doing any good.


#2

3.6L or 5.7L engine? Is this the first time the engine has seen synthetic oil?