2002 mercury grand marquis high vibrating air pressure is in the throttle body it become louder with the more gas you give the car.The vibration is the worst in the idle speed control.The vibration extend all the way down to the air filter.The air filter is not stopped up.The noise use to come and go and the car would cut off at a idle.please help me!
First, you do not have an air pressure buildup in the throttle body. There is vacuum on the inside of the throttle body and normal air pressure on the outside.
I had a 94 Grand Marquis once that developed a weird and loud moaning sound at idle. The idle speed would also drop and hunt sometimes. The cure for both issues was to replace the IAC (also called an Idle Air Bypass Valve by Ford). It was causing the vibrations.