It was my “seat of the pants” feeling that Chevron Techron makes my 1995 5.9V8 run better.

Gumout Regane,
Yamaha Ringfree
and BMW dealer sold Ventril Sauber (in German Ventril Sauber translates to “Valve Cleaner”)
also had a seat of the pants improved feel.

Texas Lubricants used to sell a “Fuel Conditioner” that had an
Amazing-to-Me ability to make the idle silky smooth.

The idle also got smoother at 260 degree F coolant temperature.

The flat piston crowns of your 5.2 probably build up a thinner layer of carbon soot than the “soapdish cavity” of a 5.9V8 piston does.