'90 Accord fluctuating idle



Hey guys, this is my first time on this forum, and i’d really appreciate any advice help people could give me.

i have a '90 accord (dx) that has an idle/throttle problem. one day i started 'er up and after a few minutes the idle begins to fluctuate rhythmically, revving from 1300rpm up to 2200 rpm, then back down to 1300, each cycle taking about a second (from 1300 to 2200 then back down). Of course, the revs only fluctuate when the car is in neutral, but when its in gear i can feel the throttle still opening up in the same rhythmic pattern, pulling me forward then backing off every second or so. The first time this happened, it also starting overheating…with possible leakage around the distributor cap, but it’s hard to tell…

has anyone experienced this? any idea on what to look for, how to diagnose, etc?

Thanks a lot!


You might have a bad thermostat, which keeps the engine from fully warming up. I once had a '85 SEI Accord did the same thing. If it really did overheat you might have something preventing coolant flow and the temp sensor doesn’t sense the hot coolant. I would start by checking the belts and changing the thermostat.


check idle air by-pass hose,they crack.