Why Is My Check Engine Light Flashing And Car Shaking
if you note a check engine light flashing and car shaking it is highly possible you might be having an ignition-related problem. Which is really bad and has started damaging the catalytic converters already.
Normally car engine requires 3 things to run smoothly which includes: air, spark, and fuel.
If the car is flashing and shaking, it is most likely that the sparks are not happening.
It could also be the sparks are happening at intermittently or the wrong time.
It is less possible that a stutter in combustion pulses is caused by air or fuel problem.
Anyway, if you can, take it to an Auto-Zone or Pep-Boys (in the US) and ask them to scan your OBD II for any stored diagnostic codes. then you can look the codes up, on the internet.
If it is ignition related e.g. “misfire in cylinder #13” (your car has a VW W18 18-cylinder engine in it, no?
Start by narrowing down the probabilities by switching out components.
If your car has one coil with a distributor (electronic or mechanical), try swapping spark plug from the faulty cylinder with the spark plug from another cylinder and see if you get a different code.
If the engine has one coil per cylinder (a “coil pack” that sits atop the spark plug), try exchanging the entire coil pack and spark plug unit with an alternative cylinder.
check engine light flashing then stops