What would cause my engine to surge? on 1990 Honda CRX

I have an '89 CRX HF and in the past week my car has stared to surge while in idle. I noticed that it only happens when the clutch is not engaged, and the battery light has come on. When I first start my car it will rev up to 2000 rpm without touching the gas, then it falls to a more normal idle speed and surges between 1000 and 15000 rpm. Also, battery light will turn off when I'm at Rpm's above 2000

by in North Hollywood, CA on November 15, 2011
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1 answer
ANSWER by , November 15, 2011
It could be many things, unfortunately and without experiencing the problem first hand or being able to do some basic diagnostic tests its hard to say. First check the coolant level, low coolant level or a bad coolant temperature switch causes a surge, a vacuum leak any where near the intake manifold will cause a surge. I think there is a combination of small ground wires near the thermostat housing passenger side of engine clean those grounds make sure they are good.The alternator or charging system may also have a fault that will contribute to a drivability problem.