my 94 accord has a terible idle surge, it goes from 1000 to 1500 for about 5 minutes than it stays at 1000 it only does it when its warm, and i noticed i only got about 270 miles outa a full tank usally i get 320?????????????

 

First, i would open the hood and look at all hoses and electrical connections to make sure nothing is disconnected, broken or loose.

Then, when it is surging, i would go ahead and smell the exhaust. Does it smell like unburned fuel?

If so, i would go and test the O2 sensor. Break out a multimeter, and when the car is warm, tap into the signal lead of the sensor. What are you measuring. THe correct voltage i think should be about .6 volts. If not, then you have a bad sensor. Replace it.

Also, you may want to clean the Throttle body to make sure the butterfly is sitting tight and not letting air pass around it.

A test you can do also is to pull the connector off the idle switch and see what the engine is doing.

fs