While second-gear starts won't give you any street cred, the W124 has ample ability to evade highway hazards and merge and/or pass with ease.

If you are unable to do this with yours, it is sufferring from a performance issue...and 13 mpg is a clue that it is...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car