We were traveling out of state and noticed an occasional momentary “dip” in power. New Concept looked at the error codes of our 2003 Olds and saw that some spark plugs were misfiring. I agreed to have all six plugs replaced and happily the problem disappeared. And they did the work the same day which is a huge help when traveling! Thank you! My only critique is that they saw other error codes and suggested repairs for 3 other systems, adding up to $$$. While I am not a mechanic I know that one of those parts (the thermostat) was replaced a year ago when the coolant pump went out. Error codes are extremely useful but must be taken in context with observations of the temp gauge by the car’s owner. Most shops recommend services off the error codes so I am not blaming New Concert here. Rather, car owners need to be involved when they are out of town and away from their regular shop.