Rough, Unstable Or Incorrect Idle, Stalling
- Inspect vacuum hoses and electrical connections. Observe ISC operation in output cycling. Watch for ISC sticking or binding while manipulating the 4 terminal ISC connector.
- Check for binding throttle linkage or cruise control cable. Check ignition system and ignition timing.
- Check fuel pressure. Fuel pressure should be a steady 9-12 psi (.6-.8 kg/cm2 ) in all speed ranges. If fuel pressure is not within specification, see appropriate A-4 FUEL SYSTEM DIAGNOSIS CHART in COMPUTERIZED ENGINE CONTROL section.
- Check for leaking or intermittent injector operation. See appropriate A-5 INJECTOR DIAGNOSIS CHART in COMPUTERIZED ENGINE CONTROL section.
- Check EGR and PCV valve operation. Check air cleaner thermostatic valve operation. Check fuel evaporative system.
- Check for loose ECM grounds. Check for rapid cycling of A/C clutch. Check P/N switch circuit. See appropriate PARK /NEUTRAL SWITCH CIRCUIT chart in COMPUTERIZED ENGINE CONTROL section.
- Check for air leak at throttle body mounting and intake manifold. Check for worn ignition distributor or internal engine components.