Sounds like spark knock then stops!

[wisemank]

1997ish SC2 4cyl. When and if hard acceleration, there is a rattle/spark knock like sound for less than 1 second then it stops. Head sounds clear nothing loose. Any ideas? The car runs fine was told it stalled on deceleration once. Not throwing any codes. Hmmmm? Thanks in advance.

Kip

[kingkevin8]

Is it a light rattling noise? Because if so it just might be your timing chain. I was thinking it was a valve train noise, but like you said, it only happens once in a while, and for a very short amount of time, but mine has been lasting longer than a second lalely. It goes on for a few seconds now, but it was for only about one when it first started. The only person that could verify this was my engine rebuilding teacher.

[Cat Fuzz]

My car does the same thing. It's spark knock. Haven't been bugged enough about it to investigate the cause.