Here's why:
* Misfire: When a cylinder fails to ignite properly, it causes a loss of power. The computer (PCM) detects this loss and increases the fuel to compensate. This can lead to a higher RPM than expected for the throttle position, because the engine is working harder to maintain power despite the misfire. The blinking check engine light is the PCM's way of saying "I've detected a critical misfire; this could cause engine damage if you continue to drive."
* Possible Causes of Misfires: Many things can cause misfires, including:
* Worn spark plugs or wires: These are common culprits, especially in older vehicles. A weak spark doesn't ignite the fuel-air mixture effectively.
* Bad ignition coil(s): The ignition coil provides the high voltage for the spark plugs. A faulty coil can result in misfires in one or more cylinders.
* Faulty fuel injectors: If an injector isn't delivering the correct amount of fuel, you'll have a misfire.
* Low fuel pressure: Insufficient fuel pressure prevents proper atomization and combustion.
* Vacuum leaks: A leak in the intake system can disrupt the air/fuel mixture.
* Engine problems: More serious problems like a bent valve, worn piston rings, or other internal engine damage can also cause misfires.
What to do:
* Do NOT continue driving: Driving with a blinking check engine light indicating misfires can cause significant engine damage. The problem will likely worsen, potentially leading to catastrophic engine failure.
* Have the code read: Get the diagnostic trouble codes (DTCs) read from your vehicle's onboard computer. An auto parts store usually offers free code reading. This will pinpoint the likely source of the problem.
* Address the underlying cause: Based on the DTCs, you or a mechanic can diagnose and repair the problem. Ignoring this could result in major repair bills down the road.
In short, the symptoms point to a severe engine problem requiring immediate attention. Ignoring this could result in costly repairs or even a blown engine. Get it checked as soon as possible.
