Idling

1987 Honda Accord LX-I mileage - 229,000

Here's my problem, I think my idling is messed up because whenever the car is in neutral (it's a 5 speed) the idling will go from fast to slow, to fast to slow, etc. I hear Hondas are notorious for this problem and even heard another one doing the same thing. It never stops and someone had suggested that it could be a problem with the idle switch and suggested that when the idle goes to high I should give it some gas and that will usually bring it back down to normal idle speed. Well, it didn't and a car that was great on gas now sucks it up like an SUV, more than my 4 cylinder automatic. Help!