Has anyone had experience using an internal engine cleaner such as Rislone (active ingredient probably kerosene)? I have a little lifter noise on #4 cylinder (flat tappet stock cam-GM lifters) and thought I would try this stuff before pulling the intake manif.The engine's vitals are terrific and there is no boost/vacuum gage fluctuations at all.The noise seems to reduce when oil pressure increases.I guess this cleaner when used for a short time (whatever the instructions suggest) would not deteriorate turbo seals etc.Thanks for looking.