Mercedes GLE V167: Why the Check Engine Light Flickers and Idle Turns Rough

When your GLE V167 starts idling roughly and the check engine light flickers rather than glowing steadily, your engine is telling you it's experiencing intermittent misfires. That flicker is not a coincidence — it typically means unburned fuel is entering the exhaust, which can damage the catalytic converter if ignored for too long. Don’t panic, but do treat this with respect.

What to check first

Start by reading the fault codes with a capable OBD-II scanner, even the basic ones will often show a P0300–P0312 range. Look for the specific cylinder misfires — that tells you where to focus. In my experience on the V167, these are the usual suspects, in this order:

• Ignition coils and spark plugs: Coils are common culprits, especially if the code points to one cylinder. The good news is that on most GLE engine variants, each coil is a separate part — you can replace just the offending coil, and often the spark plug too, rather than a whole set. Confirm the exact part for your specific engine and model year.
• Fuel injectors: A leaking or clogged injector can cause a rough idle and misfire that comes and goes. Individual injectors are usually replaceable by themselves, so if one is flagged during a cylinder balance test, you don’t necessarily need to replace all of them.
• Vacuum leaks: A cracked intake boot or a leaking PCV hose can introduce unmetered air, leading to uneven idle. A smoke test is the fastest way to find these leaks.
• Crankshaft or camshaft sensor signals: If the computer loses its timing reference intermittently, you’ll see rough running and a flashing or flickering light. Wiring harness chafing near these sensors is something I always inspect on this platform.

Is it safe to keep driving?

In short: not far, and not without checking the codes first. A flashing check engine light means active misfires are happening, and that can overheat the catalytic converter. If you’re close to your garage or home and the light is flickering, drive gently and avoid heavy acceleration. If it starts switching to a steady light and the idle clears up, you still should get it scanned soon. The longer you drive with misfires, the higher the chance a simple coil or injector fix turns into a much pricier catalytic converter repair.

This material is AI-generated and for informational purposes only — it does not replace an in-person diagnosis by a qualified mechanic.