Idle problem

[E30 Wagen]

My eta idles correctly, but only for a while. It starts at 1000rpm, and then goes down to about 650rpm. However, once I've driven it for a while and the car is at complete running temperature, it's back idling at 1000rpm. Also, when I take my foot off the gas and put it in neutral to coast to a stop, it jumps up to about 1200rpm, then settles back down to 1000rpm. I don't really know what to do at all. Please somebody tell me what I should look for.

edit: idling at 650rpm is usually rather rough

[PiercedE30]

maybe a bad/going bad afm..........

[PУCCKAЯ_e30ka]

make sure that when youre at idle in neutral the t-body is in correct place, meaning that when u open throttle a bit, there is a click in t-body

[HST]

Try cleaning the ICV with carb cleaner.

[nefarious7907]

I am having the same problem as you I have gone over everything but the ICV and AFM, I have tried to loosen the throttle cable and I have fully closed the ICV and it would still idle high. Before I had a vacuum leak and it idled rock solid at 800rpms but it was a hair rough. Now it idles smooth but too fast.

[E30 Wagen]

Try cleaning the ICV with carb cleaner.

How do you do this?

[nefarious7907]

There should be two hose on the ICV, I would assume remove them and unplug the cable attached to it and spray some carb cleaner inside of the ICV and hoses.

[lordofthewaters]

Clean the afm and the icv.................