1. Low Oil Pressure: This is the most dangerous possibility. Knocking often indicates a lack of lubrication, leading to metal-on-metal contact and engine damage. Check your oil level immediately. If it's low, topping it off might temporarily alleviate the problem, but you'll need to investigate why the oil is low (leak, failing pump, etc.). Running an engine with low oil pressure will cause catastrophic damage very quickly.
2. Fuel Delivery Issues:
* Fuel pump failure: A failing fuel pump might provide intermittent pressure, leading to fuel starvation and knocking as the engine struggles for fuel. The knocking may worsen and then cause a shutdown.
* Clogged fuel filter: A severely clogged fuel filter restricts fuel flow, causing similar symptoms to a failing fuel pump.
* Fuel injectors: A clogged or malfunctioning injector could cause a cylinder (or cylinders) to misfire and knock, eventually leading to a shutdown.
3. Ignition Problems:
* Ignition coil failure: A faulty ignition coil can cause misfires, leading to knocking and eventual shutdown.
* Spark plugs: Worn or damaged spark plugs can cause misfires and knocking.
* Distributor cap and rotor (if applicable): These parts can wear out, leading to poor ignition and misfires. (Your 1997 Talon may or may not have a distributor depending on the engine type – 4G63T has a coil-on-plug system).
4. Engine Mechanical Issues:
* Rod knock/bearing failure: This is a severe internal engine problem where the connecting rods or bearings are failing. It's a major repair or engine replacement. The knocking sound would be very pronounced and likely accompanied by other symptoms.
* Worn piston rings: Worn piston rings can cause low compression and knocking, but the shutdown after 30 seconds suggests a more immediate problem is involved.
Troubleshooting Steps:
1. Check the oil level and pressure: This is the most critical first step. Low oil pressure is a serious problem.
2. Inspect the oil for metal particles: If the oil is dark, gritty, or has metal shavings, it indicates serious internal engine damage.
3. Listen carefully to the knocking sound: Try to pinpoint the location (if possible). This can help diagnose the source.
4. Check the fuel pressure: If you have the tools and experience, measuring fuel pressure can help determine if the pump or filter are causing the issue.
5. Check the spark plugs and ignition system: Inspect for cracks, wear, or fouling on the spark plugs. Check the ignition coil(s) for damage.
Important Note: Do not continue to run the engine if it's knocking. Further damage is highly likely. Have it towed to a mechanic for proper diagnosis and repair. The cost of repairs could range from relatively inexpensive (fuel filter, spark plugs) to very expensive (engine rebuild or replacement). Early diagnosis is crucial to minimize damage and costs.
