Knocking Tapping under light load

[SeminoleViper]

New to the fourm and would love to get your guy's opinion on a noise that I have. I have a B/W 1997 GTS that when I have it in any gear and under light load it has a slight knocking/tapping noise. It is interesting because when I put the car under load it goes away completely. The noise is most noticeable around 2000 to 2500 rpms. Thanks in advance for any comments/suggestions.

[daveg]

Is it a ping, exhaust leak tick, knock or does it sound like a lifter / valve lash tick?

[SeminoleViper]

It is really odd.....It doesn't have the loud sound generally associated with a rod knock and it is not present until it gets up to up 2500 rpms in any gear. It does not make the sound if it is sitting in the garage and I have it in neutral and bring the rpms up.

[Fatboy 18]

Need video

[GTS Dean]

Those appear to be classic symptoms of preignition. You might have carbon buildup in the chambers, or low octane fuel. Depending on how loud your exhaust system is, you just might not be able to hear it at higher RPMs.