The synchronizer shaft for the camshaft position sensor can cause a loud squeak or chirping noise due to failure of the upper bushing. The noise may be erratic and is usually present when the engine is warm.Google+
Car Problem Reports
Ford Mustang Synchronizer Shaft For the Camshaft Position Sensor May Make Noise
Ford Mustang Problem
Engines Affected: 2.3L 4 Cylinder, 3.8L V6, V6
Average Mileage: 92,000 mi (78,000 mi - 130,000 mi)
Visitor, 2004 Ford Mustang, 82,000 mi
There was a loud chirping noise when the car is cold. I changed the water pump, idler pulley, belt and the sound still continued. I suspected the camshaft synchronzier and when I took it to a local mechanice he confirmed the issue. The part was changed and the sound immediately went away.It was difficult to pinpoint on my own because the sound would lessen dramatically once the car became warmer.
Visitor, 1999 Ford Mustang, 2.3L 4 Cylinder, 130,000 mi
same noise,not fixed yet!
Visitor, 2004 Ford Mustang, 80,000 mi
Car chirps when I start the car in the winter. Chirp goes away when the car is warm.
Visitor, 2004 Ford Mustang
about every 6 months it will start chirping