1) how old is your battery? how old is your oxygen sensor?

2)how oild is your fuel filter?

3)how old is your air filter?


Then you go down the line of what next for each category of fuel, air and ignition.

You need to visually inspect for torn rubber or loose electrical connections, then you need to use the search functon here as posted earlier.

I ask about the O2 sensor, because it would probably throw a code if bad, but I installed a new O2 sensor on my C230 and it starts so much better then before ( I have 108k miles )