Beginning in 1985, some engines were available with a throttle body fuel injection system and all engines were fuel injected starting in the 1986 model year. By 1992 a central multi-port fuel injected engine became available as well. All fuel injected engines are controlled by a computer which regulates idle speeds and supplies the correct amount of fuel during all engine operating conditions. No periodic adjustments are necessary or possible. If the engine is suspected of maintaining an incorrect idle speed, refer to Chapter 4 of this manual for information regarding the self-diagnostic features of the computer engine and emission control systems.