In some cases, no adverse conditions may be noticed by the driver
In other cases, there may be performance problems, such as a lack of power on acceleration and some "coughing" or misfiring. The vehicle may have trouble idling, especially when warm or when sitting at a stoplight.
Other codes may be set, such as P0300 (random, multiple misfires)
Common Problems That Trigger the P0172 and P0175 Code