seeking knowledge and wisdom from the all mighty "Forum". Collectively ya'll should spot this post, scratch your heads, laugh just a bit and remember when you too had this problem.

I am a shade tree mechanic so please use small words.

car:
1972 914-4 1.7 with stock fuel injection still in use.

Problem:
I start the car and it idles fine cold, as it warms the idle goes up to 2000rpm and even after driving an hour does not come down to a lower idle. The temp outside today in sunny FL is a chilly 72 (f)

A friend recommended stating with the air temp sensor on top the engine, so I replaced it. No change. Starts and idles at 600-700rpm as it warms the idle goes up to 1800-2000rpm.

I have no clue.

Ideas????
Jon

Could be a number of things.

Assuming you have a 4-cylinder (you stated 914-6) 1.7L with DJET FI, intake leaks are treated similarly to opening the throttle.

Perhaps the AAR is not closing. This will cause the engine to idle faster when warmed up.

first of all, oops.. was dreaming of a 6 cyl. Thanks for the correction.

I will give it to you, a 3 letter work is small. Umm, what is an AAR.

Thanks
Jon

This is your auxiliary air valve. It allows extra air when the engine is cold. As the engine warms it should close. When your engine is warmed up, carefully pull this hose that I'm pointing to off. Then plug the valve it came off with your finger. If your idle drops you found the culprit. If not check to see if the other hose going to that same valve is intact and connected to the intake plenum (the throttle body is mounted to the plenum)

AARs are known to 'coke-up' and stick. Sometimes they can be freed up by removing it and soaking the valve ports with PB Blaster.

Spray PB Blaster in the ports, then use rubber caps to keep the fluid from draining out.

Then apply 12v (+) to the hot lead and ground (-) to the body of the AAR and verify it gets hot.

From time to time, disconnect the 12v for 5~10 minutes, then reapply the power.

Do this over a 12 hour period, then drain the fluid and use a hose or compressed air (this part of the process could be a little messy) to blow the fluid out to see it the valve is operating properly in both positions (open and close - cold and hot).

If it doesn't free-up with the first session, don't give up, repeat the process a few more times ... mine took a few sessions to get back to normal

Could also be some other vacuum leak, or sticky advance in the distributor.

--DD

Check your timing
Check your distributor advance plate
Check all the vacuum lines.

thanks guys, I will start with these one at a time and see where I end up. I do appreciate it