I have this 1989 chevy truck with 5.3L and magnacharger.. 4L60E and 3.73 gears, everything was fine with the stock pulley,
i upgraded the pulley from 3.5 to 2.9 inches..
problem im having is knock during part throtle mostly in 4rth gear, how can i remove this knock problem, looks like AFR is ok and i been removing spark advance on the areas it knocks and havent removed it..
or should i go COS speed density tune?
any help ill apreciate it