IF it is the Check Engine light and not the brake warning lamp then the answer is that you have a wire that is stripped or moving back and forth causing contact of the bare wire with a metal surface that grounds the circuit and illuminates the ight. As you brake the wire swings or is pulled in one direction that shorts the circuit and causes the lamp to illuminate. When you accelerate the wire moves in the other direction or the tension is relaxed on the harness and the contact with the ground is broken so the light goes out. That problem can also be caused by a terminal for a wire that is loose in a connector that is getting pulled on as the engine moves back and forth on deceleration.the technician needs to check the wiring from the bulb on the dash panel back through all of the connectors to find the problem. It won't be inexpensive to track it down. If the problem were significant the light would stay on all the time and a code would be stored. Having driven it for a year with no adverse affects I would assume it is more of an annoyance than a 'real' problem. I guess the question is how much is it worth to you to eliminate the annoyance.hope that answers your question