brake could be the clue. We have had reports of a vibration similar to yours that is caused by the brake master cylinder not fully releasing the brakes. Have the master cylinder checked; you might need to replace it.
AU Mark 2 Ford Futura has developed a pinging noise under load on very warm to hot days with the airconditioning on. It also boiled on a 35-degree day although the temperature gauge did not indicate so and nor did the temperature light come on. The local mechanic suggested that a dirty tank of petrol may be to blame, however, I have refilled at a different petrol station and nothing has changed. I am confident that it is not a serious problem such as a cracked head/ head gasket as I am not losing coolant and the car starts perfectly every time. The coolant is fresh, as I have had a coolant leak fixed three times in a threeweek period approximately three months ago.
2008 model Ford Focus