I have a 91 Accord EX-R that idles normal in warm weather, however once the cool weather arrives as it will in Canada...my idle begins to rise and fall until the motor has reached operating temperture. (Once at operating temperture - the car idles perfectly) This fault usually appears when the fast idle is activated around 1500 rpm's its at this time that the idle drops to 900 rpm and bounces back up to 1500 rpm's. This will go on for several minutes depending how long it takes the car to reach operating temp. Has any one come across a similiar situation? Suggestions? Car has 170,000 KM a recent tune-up including air filter, oil, gas treatment. Thanks.

try replacing the distributor cap as well, they're only like 12.00. Bad seals on caps can cause funky idling, so try that, make sure that the one you buy has its new rubber o-ring in the box.

try replacing the distributor cap as well, they're only like 12.00. Bad seals on caps can cause funky idling, so try that, make sure that the one you buy has its new rubber o-ring in the box.


Thanks for the suggestion, forgot to mention I had replaced the distributor and cap (with new parts) at the same time as I did the tune-up. I have been told to look at a part that is part of the intake referred to as a diaphragm? And that it might be this part that has weakened? What are your thoughts? Thanks for your input!

Thanks for the suggestion, forgot to mention I had replaced the distributor and cap (with new parts) at the same time as I did the tune-up. I have been told to look at a part that is part of the intake referred to as a diaphragm? And that it might be this part that has weakened? What are your thoughts? Thanks for your input!

The diaphram is a vacuum controlled device that opens and closes depending on your engines needs, if you push on the the accelerator, the diaphram will open a little door in your intake to allow more air. its on the left, next to your intake box, (might be under it), it looks like alittle saucer thing, round with alitte dimple in the middle. try disconnetin the diaphram from your intake and see if that helps. If anything, just replace your intake, ebay has them cheap :biggrin:

Check the IACV (Idle Air Control Valve), the mesh screen is probably clogged with carbon. Remove the two bolts that hold it to the throttlebody, turn it so that you can see the screen, and spray it clean with carb cleaner. Let dry and reinstall. This has worked on both of my 90 Accords, and I have had others tell me that it has worked for them. Costs next to nothing, and you don't need any special tools. The entire process shouldn't take much more than ten minutes.

Check the IACV (Idle Air Control Valve), the mesh screen is probably clogged with carbon. Remove the two bolts that hold it to the throttlebody, turn it so that you can see the screen, and spray it clean with carb cleaner. Let dry and reinstall. This has worked on both of my 90 Accords, and I have had others tell me that it has worked for them. Costs next to nothing, and you don't need any special tools. The entire process shouldn't take much more than ten minutes.

Excellent! Thank you ... rdrdr ... You were dead on...My Honda feels like a brand new car!!! A Big Thanks for taking the time and sharing the information!!! Hope I can return the favour to another Honda owner in need! Thanks again!!!