My 385 has a knock on the down rev to idol...its a short and quick "knock, knock, knock"..my "service engine soon" light is on once i start driving, and i can feel the knock in my feet from driving..we pulled the valve cover to check rockers and all seems fine except one cylinder both rockers seem to move even after cycling the motor 4 times..(one should be tight, and one should be lose per cylinder correct?) i have had a history of broken pistons, but a new fuel system from Lonnies Performance solved my leaning problem...i havent pulled the head yet, because of lack of intake gasket and head gasket..
Is my problem a rod or valve? thanks

 

Have you scanned it, to determine what's turning on the SES light?

Might want to add year of car/engine.

 

thanks.. Its a 94 z28 lt1, t56 swap, d1sc w/3.4 pulley (12psi)

I have not had is scanned because of it being a sunday and the shop is closed..should that be my first step? I am assuming it is the knock sensor, but thats just a guess..just trying to get some ideas so i dont go to the shop totally unknowing..

 

You would only get a code for the knock sensor if it was defective, the wire fell off, etc.

 

i was not aware of this, thanks for the info! I wonder if it could be a mis-fire code..a friend of mine thought an injector could be dirty/defective..he told me to run some cleaner or 106 race fuel...
He is a ford man so i didnt know if i should believe him hahaha