The Chevy Impala made its debut in 1958 as "a prestige car within the reach of the average American." Chevy re-introduced the Impala in the mid-1990s as a family sport sedan with a Corvette-derived engine and classy monochromatic color scheme. The following details for the installation of a new throttle body on the 1985 Impala specifically. Other engine offerings in other model years may require slightly different procedures.
Relieve the pressure in the fuel system, taking care not to spill or spray gasoline. Disconnect the battery ground cable. Take the THERMAC hose off the engine fitting and then lift off the air cleaner.
Label and disconnect all the electrical connectors from the idle air control (IAC) valve, the throttle position sensor (TPS) and the fuel injectors. Disengage the throttle linkage, the return springs and the cruise control cable.
Tag each of the vacuum hoses that runs from the throttle body and then disconnect them. Label and disconnect the fuel supply and return lines. Take out the fuel line O-rings and throw them away. Plug the fuel lines with golf tees.
Take off the fasteners that hold the throttle body to the intake manifold. Lift the throttle body and the gasket from the manifold. Cover the intake manifold with a clean shop rag to prevent dirt and debris from entering the engine.
Clean the gasket mating surfaces of all dirt, debris and gasket material. Use a new gasket and install the throttle body to the intake manifold. Tighten the fasteners to 11 foot pounds of torque.
Use new o-rings on the fuel lines and reconnect all the fuel supply and fuel return lines to the throttle body. Reconnect the throttle body vacuum hoses in the order they were disconnected. Reattach the cruise control cable.
Reconnect the electrical connectors for the IAC, the TPS and injectors. Place the air cleaner on the engine, then connect the THERMAC hose.
Attach the negative battery cable to the terminal. Start the engine and allow it to run for several minutes. Check for fuel leaks.
