* Misfire(s): This is the most probable cause. A misfire occurs when one or more cylinders aren't combusting properly. This can be due to several factors:
* Spark plugs: Worn, fouled, or damaged spark plugs are a common culprit.
* Ignition coils: A faulty ignition coil prevents the spark plug in a specific cylinder from firing correctly.
* Worn or damaged wires: High voltage wires carrying the spark to the plugs can crack or short, causing misfires.
* Fuel injectors: A clogged or malfunctioning fuel injector can prevent the proper amount of fuel from reaching a cylinder.
* Low fuel pressure: Insufficient fuel pressure can lead to inconsistent combustion.
* Valve issues: Burnt or sticking valves can prevent proper combustion in a cylinder. This is less likely but possible.
* Damaged piston or rings: Severe wear and tear in the engine can lead to misfires, but this is usually accompanied by other symptoms like excessive smoke or loss of compression.
* Crankshaft Position Sensor (CKP) or Camshaft Position Sensor (CMP): These sensors tell the engine's computer the position of the crankshaft and camshaft, crucial for proper timing. A faulty sensor can cause misfires and rough running.
* Mass Airflow Sensor (MAF): A faulty MAF sensor provides inaccurate readings of the air entering the engine, leading to poor fuel mixture and potentially misfires.
Why it's worse at low speeds and in gear:
The increased load on the engine at low speeds while in gear (especially if you're accelerating) exacerbates the misfire problem. Under these conditions, the engine needs more power, and a misfire becomes much more noticeable. At higher speeds and lighter loads, the engine might compensate for the misfire slightly better.
What to do:
1. Don't drive it further: Continuing to drive with a blinking check engine light and a severe misfire will likely cause more damage.
2. Get the codes read: Take your vehicle to an auto parts store (like AutoZone or Advance Auto Parts) and have them read the diagnostic trouble codes (DTCs) from your car's computer. These codes will give valuable clues about the specific problem.
3. Professional diagnosis: Based on the DTCs, a mechanic can diagnose the exact cause of the misfire and recommend repairs. This is crucial because a simple spark plug issue is much cheaper to fix than a serious engine problem.
Ignoring this problem could lead to catastrophic engine damage, potentially requiring a costly engine rebuild or replacement. Get it checked out immediately.
