I have noticed recently I'm getting a metal on metal knock when accelerating at 40-50 mph. It happens when the truck downshifts, revs to where it should shift, then starts knocking HARD. It goes away when I let off and acelerate lighter. It has happened on Edge lvl 2 and Stock tuning so it's not the Edge. Have been running Stock for about 150 mi and it still does it. Has happened using Chevron, Exxon, and BP gas. This is definitely not pinging due to lean. Anyone else had this problem? It is still under warranty so I think this is something I should have looked at but thought I check here first. Thanks for your help!

 

Since it's under warranty, I agree that you should take it in. Have you tried accelerating in 4x4 as well to see if the noise is there? Just curious since several people have had issues with the IWE and vacuum solenoids.

 

No I haven't, this is definitely in the engine.