What Causes Unstable Idle Speed in Natural Gas Vehicles?

[HaleyDella]

Unstable idle speed in natural gas vehicles may be due to uneven combustion of natural gas. Specific causes: Clogged idle air jets, malfunctioning idle control devices, weak spark in individual spark plugs, poor valve sealing, intake manifold leaks, incorrect ignition timing (too early or too late), or improper idle speed adjustment. Solutions: First, adjust the idle speed. If the issue persists after adjustment, check if the idle jets and idle air jets are clogged. If clogged, clean them with gasoline or acetone and blow through with compressed air. If not clogged, stabilize the engine at a certain RPM and listen for air leaks at the intake manifold or carburetor gaskets. If leaks are found, tighten screws or adjust gasket thickness to resolve.