Possible Cause & Correction

Check the following items:

• Visually check vacuum hoses for splits, kinks and proper connections as shown on Vehicle Emission Control Information label.
• Check ignition wires for cracking, hardness and proper connections at both distributor cap and spark plugs.
• Check wires for pinches, cuts and proper connections.
• Check fuel pressure.
• Check for poor quality or water contaminated fuel.
• Check for fouled spark plugs.
• Ensure the installed PROM is correct for that particular vehicle. Check with dealer for latest application information.
• Check for a binding or sticking TP sensor. Voltage should increase steadily as throttle is moved toward Wide Open Throttle (WOT).
• Ensure PCM-controlled idle speed is correct.
• Check EGR operation.
• Check engine cooling system thermostat for proper operation and heat range.
• Check ignition control system ground circuit.
• Check canister purge system for proper operation.
• Check charging system output. Repair charging system if voltage is less than 9 or more than 17 volts.
• Check fuel injectors. Perform INJECTOR BALANCE TEST in SYSTEM/COMPONENT TESTS article.
• Check injector harness locations. Ensure injectors are connected to correct injector/cylinder according to firing order.
• Check heated oxygen sensor ground (corroded threads in exhaust manifold).
• Check for air leaks between MAF sensor and throttle body.
• Check air induction system for restrictions.
• Check for intake valve deposits.
• Check MAP or MAF sensor.
• Check distributor vent system (if equipped).