94 Sable...Intermittent idle problem

[GuyInWi]

Sedan, 3.0 V6
Ok, here's the list of symptoms. High idle problem that seems to be heat related.
In cold weather it will run fine until you have sustained speed of 65 to 70 for at least 45 minutes. In warm weather it will go into high idle whenever the mood strikes, be it a block from home or 10 miles down the road.

After cruising at 65 to 70 and it acts up the check engine light comes on for 5 to 30 seconds and it won't store a code. If I hold it at 65 when it acts up, it will shift in and out of over-drive repeatedly. If I bump it up to 70, it will still shift in and out of OD, but not nearly as often.

There is only one chance to make it go into high idle, and that is the sustained speed of 65 to 70 for 45 minutes or more.

My first inclination is the TPS, but since it won't store a code, I hate to start throwing parts into it.

Any ideas?

[DistanceGuy1]

It could be a faulty or dirty mass air flow sensor. Rather than throw bucks at changing it out, try cleaning it with a can of CRC Mass Air Flow Sensor cleaner. Your local Autozone or other such comparable auto parts chain store should stock it. Start there ...for the <$12.00 makes sense.

[GuyInWi]

Ok, I cleaned the mass air flow sensor as well as the IAC which was pretty rough. I noticed an immediate improvement in the initial idle at a cold start. I took it on a trip and did the sustained speeds of 65-70 for a couple of hours, and it never acted up. Also, the mileage for that trip was 25, which is back where it was when I bought it 4 1/2 years ago.

So, I believe the problem is handled. I won't know for sure until we get warm weather and it continues to behave.
Given how clean the mass ari flow sensor was and how dirty the IAC was, the IAC appears to have been the culprit.
Thanks to DistanceGuy1 for the tip.

[DistanceGuy1]

You're welcome....glad to hear some of the issue is now gone.. we all get decent tips from these columns.

With regard to the IAC...that is one part you might want to change out when the warmer weather hits. Relatively inexpensive and not too bad to access.