Preliminary Checks

Check or perform the following items before beginning diagnosis of fuel injection system:

• Check vacuum hoses for cracks, kinks, and proper routing.
• Check for air leaks at throttle body flange and at intake manifold.
• Check ignition system.
• All electrical connections and terminals (including battery).
• Perform DIAGNOSTIC CIRCUIT CHECK. See GENERAL MOTORS COMPUTER COMMAND CONTROL article in COMPUTERIZED ENGINE CONTROL section.
• If engine cranks but will not run, see CHART A-3 in GENERAL MOTORS COMPUTER COMMAND CONTROL article in COMPUTERIZED ENGINE CONTROL section.