1993 Accord EX coupe

Symptoms:

When accelerator is not applied, the engine surges from idle (around 1k) to around 2500 rpm with a frequency about once every four seconds.

Also, it overheated this morning when i was idling in traffic for about 15 minutes.

History:

Replaced fan and radiator cap last month when it was overheating.

A friend said perhaps the engine was surging to keep up with an electrical load, possibly another defective fan. What do you all think?

 

The engine is surging b/c the idle air control valve is not getting any coolant. Either you have a coolant leak or a air pocket in the coolant system.