Hey everyone,

My friend has a 2000 Civic DX hatch with a D16Y7 and a manual transmission, and the car usually drives fine but if it's in stop and go traffic the "idle" RPM starts rising when you're in neutral or clutched in. It goes up slowly but if you're in traffic for a while it will rise to like 3000 RPM when you're not touching the gas. The temperature guage doesn't go up or anything so it's not overheating per say, but it behaves like this only in situations where it would overheat if it had problems with the cooling system.

Any ideas on where to start? The shop couldn't replicate the problem, but I hope it's something that can be tracked down... I tried searching but it's a pretty specific problem so it doesn't help using vague keywords.

Thanks

 

Any CEL codes?

 

The light isn't on, but I'll try jumping it with a wire and see if it's throwing anything when I see the car tomorrow.

(It's possible for it to be throwing a code without the CEL being on, right?) It might have come on for a day or something a week or 2 ago.

 

If the CEL turned on, the code is still stored in the ECU, unless you have reset it.

 

Could possibly be a vacuum leak?
I wouldnt think so but try to pull the CEL and see what comes up.