I take help from online websites that have this service like helping in repair some like reliable-store have instant help.. others are a bit slow which I don't prefer... rest is up to u.. U can also get free manuals
Hi,you are looking at a fully sinfetic oil,ask at a main deelers they will put you in the right direction,dont just go to your local shop they might sell you eneything,get the propper oil for your car.
If it has not set a check engine light it likely is not a misfire, these models wear out the engine and trans mounts by about 80,000 miles. if it is misfire you will need to read the fault codes and go from there.
Question edited for a lot more clarity.
Question moved to model category.
Sometimes the are just on, and sometimes the SRS will flash. Connect to a pro grade scan tool computer and look for the diagnostic trouble codes associated with the fault status.
https://www.google.com/search?q=Mercedes+W169+SrS+system+light+on
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Question edited for a lot more clarity, and add maker.
Question moved to maker category.
These are all function of the Body Control Module. You need an auto electrician with a pro grade scan tool computer and access to factory technical bulletins.
https://www.google.com/search?q=mobile+auto+electrician+near+me
No clues in here.