Hello all...I have a spark rattle, and higher grade of fuel dosen't seem to help at.
It's 94 bmw325is.

It is a manufacture provided service procedure to flash the combustion chamber with steam to force the carbon to break free from the piston face and valve face.

With the engine at normal operating temperature and approximately 2000 RPM, allow the engine to ingest by a vacuum hose 12 oz soda can of water.

A puff of steam and the carbon is gone.

The ChevRON TechRON is to clean the back side or tulip of the valve
and all components on the fuel path, of varnish.

You can use as often as needed.

This is a must deal if you are near a pinging point and using forced induction.

Later,