I am getting this knocking sound which sounds like pinging between 3k to 4k rpm. The frequency increases as I accelerate and it also occurs when I am off the gas. Can pinging occur when I am off the gas? My PowerFC does not pick up this sound as pinging on the knock monitor. Even then the knock sensor may not be entirely accurate. It started about a week after I changed my engine oil to Mobil 1 5W50. Would this be symptoms of a valve lash issue or pinging?


Modified by garyc17 at 11:12 AM 5/4/2007

 

Okay, I've adjusted my tappets. Most of them were in spec. I am still getting that knocking sound on deceleration. What could be the problem? Can old plugs cause this problem even though they look okay? I even reduced my ignition timing by 2 degrees between the knocking range of 3k rpm to 5k rpm, but no improvement. Should I retard the timing further? I did not adjust the fuel map though.

 

I've just switched to a different fuel brand. Also restored my tune to that of my tuner. This is to check if its a fuel quality issue. Seems to knock slightly lesser(placebo?). Could this be my 12.5CR? I've always used RON98 petrol.