markvrs

If your ECU has been remapped to give pops and crackles on overrun it will have been set at at a specific rev limit, normally from SAWS and K-Maps at 3000rpm

If you have pops on all rev range, just louder with more revs, most likely a fault, if pops have a clear limit, say none below 3k, then likely you have a remap. MEMS 3 as standard does not over fuel on over run without a lot of provocation.