Q: car shakes when AC is on,or when I get to red light it will start shaking even if the AC is not on. Its a Acura tsx 2006 159mi

Assuming there is no serious mechanical problem, such as uneven cylinder compression, you have either an engine management fault, that is a deficiency in the ignition, fuel or air induction systems, or possibly faulty motor mounts. To check for engine-mount problems, you can try shifting from "neutral" to "drive" and back, while the engine is running. If the vibrations disappear or reduce dramatically in "neutral," it’s likely that you need new engine mounts. Whenever there is excessive engine vibration, mechanics first rule out engine operating conditions. For example, rough running at idle can be caused by faults in the air induction system as well as the ignition and fuel systems. If you want the running condition of the engine evaluated by a certified Mechanic, dispatched by YourMechanic right to your location, please request a rough idle diagnostic. To evaluate the motor mounts, request an engine vibration diagnostic. Regardless of which of the two services you request, the underlying fault (root cause) of the issue you are writing in about will be identified for you, along with a recommended repair strategy and cost. If you do end up replacing motor mounts, genuine OEM mounts are highly recommended in order to maximize the chances of resolving the problem. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.