Idle to fast after highway driving

[me1303]

Hi, I am new here and hope I can get some help...

I have a 2001 Saturn SL1. I do a lot of highway driving. Last year when the weather turned cooler I started having a problem with my idle not kicking down to 750 after driving highway speeds and coming to stops at red lights, etc. The idle would run at about 1400-1500 until I stopped the engine and restarted the car. After doing that, it would run normal with idle staying at 750. I don't have the problem during the summer. Now that the weather is turning cooler again, the problem has resurfaced.

Things I have done to try and correct - taken the throttle body off the car, cleaned it and reinstalled. My Saturn dealer did an upper engine flush and cleaned the fuel injection system. The problem keeps coming back.

Does anyone have a suggestion to correct this?

[samprix]

Make sure that your engine coolant temperature is running in the normal range. Could be that the thermostat needs replaced and/or the engine coolant temperature sensor and connector needs replaced.
A new ECTS fixed a number of drivability problems on my SL-2

[travist]

Best bet would be the TPS sensor. Next time it happens, open the hood and tap on that sensor. It is located on the side of the throttle body, with 3 wires going into it. It the idle drops after tapping on it, replace it.

[me1303]

Thank you for the suggestions. I will keep them in mind the next time it happens. It warmed up here so I have not had the problem lately. The cold weather will be coming back soon.