Preliminary Checks

Most driveability problems in the throttle body fuel injection system result from faulty wiring and/or leaking vacuum hoses and hose connections. To avoid unnecessary component testing, visual check should be performed before beginning trouble shooting procedures. A preliminary visual check should include:

• Air ducts at air cleaner and throttle body.
• All electrical connections at components.

Check vacuum lines for tight leak-free connections in these areas:

• Throttle body (2 front, 2 rear).
• Purge solenoid.
• Charcoal canister.
• PCV valve to intake manifold vacuum port.
• EGR backpressure transducer.
• MAP sensor. Ensure the following electrical connectors are properly attached:
• 60-pin and 14-pin SMEC connectors.
• MAP sensor connector.
• Purge solenoid connector.
• Speed sensor connector.
• Throttle body temperature sensor connector.
• Radiator fan relay connector.
• AIS motor connector.
• TPS connector.
• A/C cut-out relay.
• Ground eyelet on left cylinder head.
• Fuel injector connector.
• Oxygen sensor connector.
• Coolant temperature sensor connector.
• Distributor connector.