Q: Car hesitating when accelerating.

There are many sensors on a car that the computer relies to tell it what is happening. Things like engine temperature, air density, elevation above sea level, ambient temperature, etc., are all readings that your cars computer uses to determine how much fuel to inject at specific times. A faulty sensor that is sending the wrong information will cause things to go out of balance. This can translate into a hesitation, a stumble, bad gas mileage, loss of power, etc. Even though there is no warning lights, the cars computer can still have what are known as "soft" or "pending codes" stored. These are codes that do not turn on a light but are still stored in memory. Also Freeze Frame data records may be stored in the computers memory as well. These Freeze Frames are recordings that your cars computer takes of what is happening when your vehicle is acting up. They contain vital information that a technician can use to help diagnose the issue. A technician should be able to scan, extract, and interpret that information for a proper diagnosis.