I have a 1986 honda civic that won't idle periodically. Never happens when its cold. Sometimes it runs perfect. At all other speeds it runs perfect. No missing, etc. its only the idle. When it does act up the minute I push the clutch in the tach needle falls down to zero and the car stalls. It always starts right up. If I undo the gas cap it will sometimes run okay again for a short time then start again. I did replace the gas cap but it didn't help. Could the pcv valve cause this? I have never found it on this car so that's also my next question. Where is that thing? There is a lot of blow by around the oil cap too. Car has 140,000 on it.

Sounds like your Ignition Control Module (igniter) is bad:

Zip Code Entry at PartsAmerica.com (http://www.partsamerica.com/ProductList.aspx?PartType=194&PTSet=A&SearchFor=Ignition+Module%2fControl+Unit)

Thanks grease monkey! I dived into the dist. cap and took it out and at least cleaned the connections. It probably won't help but I had extra time on my hands and wanted to explore that area! I'll be driving today so I'll find out. I spare parts car but the distributor is gone. So my intent was to swap it out, until I saw the dist. was gone on that car! Dang!

Do you know where the pcv valve is on the 86 civic? 1.5 engine? I have read and looked all over for it and ican't find it. Its never been changed since I've had the car. I bought the car for 200. It was wrecked so I fixed it and got it running. But that's about the only maintenance piece that I still haven't done. Thanks again for taking the time to answer all of us!!

Should be located on the intake manifold, just below the fuel rail on the driver's side. There should be a vacuum line going from the throttle body to the PCV valve. It presses into a rubber grommet in the intake manifold.

i have a 1986 honda civic that won't idle periodically. never happens when its cold. sometimes it runs perfect. at all other speeds it runs perfect. no missing, etc. its only the idle. when it does act up the minute i push the clutch in the tach needle falls down to zero and the car stalls. it always starts right up. if i undo the gas cap it will sometimes run okay again for a short time then start again. i did replace the gas cap but it didn't help. could the pcv valve cause this? i have never found it on this car so thats also my next question. where is that thing?! there is alot of blow by around the oil cap too. car has 140,000 on it.

Hey guy I'm having the same problem with my 86 civic, so if you figure it out before I do dope me a line an ill do the same. Thanks phantomstranger