Any idea what else this could be....sounds like a light tapping......like a knock...i thought at first it was just valvetrain noise but im beginning to think otherwise. Car runs strong as can be and only has 77K on it. Has had a pretty mild life.... 94T/A A4....Help!

 

Get a stscope and check the front of the engine; I had something like that happen to me. Turned out to be broken teeth on the backside of my timing gear.

 

Does the tapping increase and or get louder with rpm?

 

I cant notice it once the engine revs up.........

 

well, i had a similar sound on my 97 m6. it turned out being the tensioner pulley....the spring had lost some tension for some unknown reason and made a tapping noise from vibration at idle. revved it up and it would disappear. i replaced the pulley and that was the end of that. i've not heard your car to say if its that, but if you take off your belt it should be easy enough to tell.

 

Keep the oppinions coming!!!!....ill try the belt thing in the morning......

 

Rod's don't knock at idle or under a load unless they are fixing to window the block.
Take it out on a quiet road and run about 40 in 4th gear and find the sweet spot with no accel and no decel,ya know right as it seams to float.If it is a rod you can hear it then.If you have loud exhaust you may not hear it,but that is the best way to hear a rod. You may have to try it several times to find the spot in the gas pedal.

 

Keep em comin

 

I asked cause it happened to me and it didn't window the block.It shattered the piston skirt and chewed the head up bad top the point I couldn't get the spark plug out of the head.

 

got a tick ( not a header leak ) that i could only here at a certain rpms, due to longtubes/borla. anyways, next time i ran it, rod broke...

 

never heard this one. I have heard many rods knocking and you could hear it at idle and especially under a load.

 

Well your name "Mr.Nitrous" doesnt help the motor any bit...

 

sure it does...shoot a 300 shot through there and you won't hear that tapping anymore. j/k.....have you checked the lifters yet? One may be collapsed.

 

The car has never ran Nitrous...it is bone stock, everyday driver. I havent taken anything on it apart yet......trying to get some oppinions before i dig into it.

 

I'd take the valve cover off of each side, one at a time, and run it.
If its a lifter or any in the valve train you should be able to tell.

I think the best way to describe rod knock is the "marble in the intake sound."

Exhaust leaks can get pretty load as well.
Good luck I hope its something easy.