yes and no. seafoma does very good , when sucked through your brake booster line. ive used it in my gas before, and never noticed much of anything happening. its more of a solvent/cleaner, than a gas additive. you can also pour it in your crankcase, just before you change your oil! i woudlnt run it in my oil, after an oil change, since its a cleaner, it'll probably remove or not allow oil to lube where it should. onliy in oil beofre oilchange, pour in, start car, run ofr 10 or 15 minutes idling, then drian out with oil. thy also make a spray can called deep creep, its a foamy version. you spray it through yur throttle body, before oil change let it sit, for 15 minutes maybe, start car, and it will clean your combustion chambers, lots of smoke, but yuor gunna have to change yuor spark plugs and oil after, as it fouls them.