* Spark Plug Issues: Worn, damaged, or fouled spark plugs can't deliver a consistent, strong spark. This can lead to incomplete combustion, causing the unburnt fuel to ignite in the exhaust system, resulting in a backfire.
* Spark Wire Problems: Cracked, frayed, or poorly connected spark wires can cause misfires or a weak spark. The same incomplete combustion problem applies, leading to a backfire. A wire that's arcing to ground will also cause misfires and potential backfires.
While other issues (like ignition control module, distributor cap and rotor - if so equipped, etc.) can also cause backfires, spark plugs and wires are among the most common culprits. If your Windstar is backfiring, inspecting these components should be a high priority in your troubleshooting.
