Visual Inspection

All PFI diagnosis should begin with a thorough visual inspection. Visual inspection can often lead to repair of a simple problem without use of the charts. An example might be an unstable idle complaint with history code EO30. Visual inspection may reveal a vacuum hose disconnected or a spark plug wire disconnected or cut, ISC not connected or ISC connector not latched, or other obvious causes for an unstable idle condition;

• Inspect all vacuum hoses for being pinched, cut or disconnected. Be sure to inspect hoses that are difficult to see such as beneath the upper intake, generator, etc.
• Check for proper ground connections, ground eyelets connected to ground points, star washers installed, if applicable.
• Check both battery positive junction blocks for loose retainer nuts.
• Inspect other wiring in the engine compartment for good connections, burned or chaffed spots, pinched wires or harness contact with sharp edge, or hot exhaust manifolds.
• Check for blown or missing fuses and for relay, missing or installed in the wrong locations.
• Inspect plug wires for proper routing, connection, cuts, visible signs of arcing to ground.