I have had this issue for a few months now, but it has never been so bad that I felt like I had to take it in for service. When I finally did, the dealer could not find anything wrong with it.

Whenever I am stopped (usually with the A/C on) my car has a moderate "clunk" noise and shake that happens intermittently. It happens every few seconds, and then stops, and starts again. Has anyone had this experience? Any help or ideas would be GREATLY appreciated.

 

A chief diagnostic point is if the clunk ONLY occurs with the A/C on. If it occurs regularly enough, try turning the A/C completely off while the intermittant event is occurring. If doing so makes the vibration go away, it most likely is in the A/C compressor, its mounting, or it being overcharged or developing overpressurization. A fractured engine mount can also act this way, since the instant load of the A/C compressor engaging can rock the engine on the loose or broken mount.

If not related to the A/C, areas to check include the harmonic balancer/crank pulley assembly for tightness and evidence of cracks, engine mounts (again), and the bolts holding the transaxle to the engine. Occassionally, a transmission lockup device (in the case of the Escape the TCC - Torque Converter Clutch) will try to engage due to a fault in its control circuit. But this usually stalls the engine at idle, since a successful lockup mechanically links the engine to the drive wheels.

A loose alternator can also shake the engine intermittantly, since a change in charge load makes the alternator shaft easier or harder for the engine to turn.

And, a loose electric cooling fan assembly that is cycling on and off at idle can make a clunk, although it usually is not strong enough to shake the car.