Abstract: A fuel additive composition comprising: a) a Mannich condensation product of (1) a high molecular weight alkyl-substituted hydroxyaromatic compound wherein the alkyl group has a number average molecular weight of from about 300 to about 5,000 (2) an amine which contains an amino group having at least one active hydrogen atom, and (3) an aldehyde, wherein the respective molar ratio of reactants (1), (2), and (3) is 1:0.1-10:0.

Abstract: A fuel composition comprising a major amount of hydrocarbons boiling in the gasoline or diesel range and (a) about 50 to 70 parts per million by weight of a fuel-soluble aliphatic hydrocarbyl-substituted amine having at least one basic nitrogen atom wherein the hydrocarbyl group has a number average molecular weight of about 700 to 3,000; and (b) about 35 to below about 75 parts per million by weight of a hydrocarbyl-terminated poly(oxyalkylene) monool having an average molecular weight of about 500 to about 5,000, wherein the oxyalkylene group is a C.sub.2 to C.sub.5 oxyalkylene group and the hydrocarbyl group is a C.sub.1 to C.sub.30 hydrocarbyl group.