I went for my annual inspection sticker today, I've been driving the convertible probably 150mi a week for the past month.

The inspector took my car into the bay, I had the key in my pocket in the waiting area so I took it out to him and dropped in the cupholder "in case you need to start it again". and he was hooking up the ODBC reader thing.

The car passed inspection, he pulled up to the pump for me and filled it.

When I restarted it and left it was running rough...the "check engine light" comes on within 200ft. I swing it around and go back...he assures me nothing could have happened during the inspection...and that the light couldn't have been on before..and that the car is obviously running a cylinder down. he hooked his obdc tester to it and confirmed. He says "definitely a coil, it happens, bad luck".

is it? what are the odds that this car throws an error within seconds of an inspection.

Just as good as any other time I would say.

true...I was hoping someone would write in and say "are they nuts, you never plug in a OBDC tester while the car is running!" or "your inspector is a crook" or "never let a guy who you can't trace back four generations into germany touch your car".

Sorry I couldn't be of help but stranger things have happened. I would definitely have a look around the engine bay and make sure something is not just unplugged or damaged.

Make sure the plugs for the coil are all properly connected and the spark plug are pushed in all the way. Also, check the connection for the fuel injector.

So, was the coil loose? Did the "tech" check the timing and "by coincidence" it was the same coil?

THANKFULLY Der Peoples Republik of Kalifornia has gotten one thing right - smog checks for 2000 and later cars don't involve a "tech" doing anything more than plugging into the OBDII port with a laptop. The laptop runs Der Peoples' software which checks whether any failure codes are active and if the ECU can run internal diagnostics. No more timing checks and no sniffer test, just an ECU check. "Techs" are supposed to open the hood and perform a visual inspection, but they don't. Last I heard, 22 states are doing the same thing. Hopefully your state adopts the policy soon.

Mass inspections only use the OBDII port.

I took the car to a local indy shop, I told him I needed service B, check the brake pads, and check the misfiring cylinder. (I had budgeted $2k for this at my dealer)

I stopped by the shop and asked him if he had an opinion of my 7cyl amg. "that's a beautiful motor, I love those cars, the power is fantastic, your motor is in great shape, you're looking at another 100kmi on it easily"

He thought the sparkplugs looked old, a possible cause of the coil failure. he replaced 8 plugs and one coil, and advised if another coil failed he'd do the remaining 7. He checked the oil and said there was no reason to replace it with only 5kmi on it, it looked new, he said he'd send it out to be tested if I wanted but to save my money.
The shocker was he told me the pads had another 5 to 10k on them depending on how i drove it, he said if it was my summer car to bring it back next spring. I was thrilled to get out the door for $700.

Why would he only replace half the plugs or did they go back to 8 on the 63?

NFC! He said he swapped all the plugs and one of the coils...silly me, I assumed that each coil sat directly on top of a plug..

The m156 only has one plug per cyl.

Well that makes life a little cheaper.

schorert1 you are right it is COP

I guess I am old school with my 55 and 16 plugs and wires to change out.