Possible Cause & Correction
Check the following items:
- Check fuel pump relay. See FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 3.0L SATURN "L" SERIES article.
- Check for open injector fuse(s).
- Check for poor quality or alcohol contaminated fuel. See ALCOHOL/CONTAMINANTS-IN-FUEL DIAGNOSIS WITH SPECIAL TOOL or ALCOHOL/CONTAMINANTS-IN-FUEL DIAGNOSIS WITHOUT SPECIAL TOOL under SYSTEM & COMPONENT TESTING - 3.0L SATURN "L" SERIES article.
- Check for binding or sticking TP sensor, or high TP sensor voltage with throttle closed.
- Check EGR operation.
- Check for leaking fuel injector. See INJECTOR LEAK TEST under SYSTEM & COMPONENT TESTING - 3.0L SATURN "L" SERIES article.
- Ensure resistance of Engine Coolant Temperature (ECT) sensor circuit is within specification. See Figure .
- Check resistance of ECT and Intake Air Temperature (IAT) sensors. On a cold engine, ECT and IAT sensor readings should be within 5°F of each other. See Figure .
- Check for proper spark output using Spark Tester (J-26792).
- Remove spark plugs and check for wet plugs, cracks, improper gap, burned electrodes or heavy carbon deposits.
- Check fuel pressure. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES - 3.0L SATURN "L" SERIES article.
- Check for plugged injectors. See FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - 3.0L SATURN "L" SERIES article.
- Check for loose ignition coil ground and power feed circuit connections. Also check ignition coil fuse.
- Check for faulty in-tank fuel pump check valve (if equipped). A faulty in-tank fuel pump check valve will allow fuel to drain back to tank after engine is stopped. To check this condition, turn ignition off, disconnect fuel pressure line at fuel rail and remove filler cap. Using a radiator pressure tester, apply 15 psi (1.0 kg/cm2 ). If pressure holds for 60 seconds, check valve is okay.
- Ensure the installed ECM program is correct for the particular vehicle. Check with dealer for latest application information.
- Check for restricted exhaust system, such as a damaged or collapsed pipe, muffler or catalytic converter. See RESTRICTED EXHAUST .
- Check Idle Air Control (IAC) system. Check for vacuum leak at high idle. Check for binding of throttle blade or linkage. Check for foreign material in IAC bore of throttle body. Check for proper connection of IAC valve electrical connector. Check for failure of A/C compressor or relay.
- Check Manifold Absolute Pressure (MAP) and/or Mass Airflow (MAF) sensor. Check air intake tube for air leaks, blockage or damage.
- Inspect Crankshaft Position (CKP) sensor clearance and resistance. Check harmonic balancer interrupter rings for bent or missing vanes.
- Check if PCV valve is stuck open.
- Using a scan tool, check the Idle Air Control (IAC) operation.
- Check basic engine mechanical problems (i.e., compression, head gasket(s), valves). Check for incorrect valve timing, bent push rods, broken valve springs or worn camshaft lobes.
- Check ECM and engine grounds for correct locations, tight and clean connections. See WIRING DIAGRAMS .