Your mechanic functions as a car doctor, so they would most likely ask you for symptoms if you request them to tune-up your vehicle. Before they recommend any mobile car repair, they will want to diagnose it first. To do this, they would have to conduct tests. Fortunately, you can speed this up by telling them what occurs, when it happens, what you hear and what you feel when the “illness” pops up. Here are the symptoms you should watch out for:
A Clogged or Dirty Engine Filter
Based on studies the EPA conducted, a dirty or clogged engine air filter has more chances of reducing acceleration instead of fuel economy. This is because these filters gradually become dirty over time, so you will probably experience a subtle, but steady performance loss. It happens until your accelerates like a turtle. If you still have not changed your air filter for over two years (or less for places with plenty of dust in the air), then this could be the issue.
A Misfiring Engine
This happens when spark plugs flare up at the wrong time and are caused commonly by ruined or damaged spark plugs. Moreover, worn spark plugs can also cause sluggish acceleration, fuel economy and hard starting. However, the majority of plugs commonly run for 100,000 miles or more. Besides, engine computers do a great job in compensating for bad plugs, so this could not be the only or primary culprit.
Since some symptoms also appear in other issues, it would be best to have a professional mechanic check your car first. Instead of suggesting a tune-up yourself though, describe what your car has been going through. He will be able to determine what your vehicle needs, what its real diagnosis is and how to address it.