check the recalls for the 99 Mercury Cougar!! it includes a recall on the throttle cable...
Yes, either can cause a shake while driving.
Perhaps your timing.
shake
shake
shake
Low pressure in the tires can cause shaking, the alignment can cause shaking also.
One reason that your truck might start to shake when the gas pedal is pressed is because the tires could need to be balanced. The problem could also be your shock absorbers, or struts. * It has less to do with the gas pedal as it has to do with parts affected by acceleration.
Can be a bent wheel, tire out of balance, or worn suspension parts.
rattle
to quiver or shake a lot and to vibrate
Look for a broken blade on the radiator cooling fan(s), if one is cracked, it will throw the whole fan off balance.
pencils vibrate when someone moves it or shakes it.pencils also vibrate when there's an earthquake.