I have a '86 Accord LXi winter beater and the problem is that when the temperature gets going the idle surges between 1200 and 1900 rpms. Has any one ever experienced this problem or have any suggestions? The dealer told me it might be the temperature sensor. Anyone know where this is located on the engine?

 

Could be the temp sensor..
Could be the coolant level..
vacuum leak..
fast idle valve..

hmmm.. if it happens after the car is already warmed up.. I would have to think its the fast idle valve being its an LXI.. Did these things even have a fast idle valve?

someone help me out here please..

 

Come to think about it.. coolant temp sensor could also be a culprit after the car is at normal operating temp..

What is happening is that your ECU is trying to find the proper idle range but cannot find the proper response from the involved sensors.. when this happens, the ecu will "hunt" for that unknown range and cause the idle to fluctuate..

Coolant Temp Sensor(TW) would also be a good place to start if the coolant level is ok..
It should be located where the upper radiator hose meets the engine cylinder head?, 2 pin connector.. note that the Thermal Switch is also located there and can be easily confused with the TW switch..

 

Fast idle valve should be replaced or checked first.