# Car stalling while idling in cold weather **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** cadillac, sts\ **Created:** [September 4, 2017, 11:13pm UTC](https://community.cartalk.com/t/car-stalling-while-idling-in-cold-weather/107537 "2017-09-04T23:13:05Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![a4scody](https://avatars.discourse-cdn.com/v4/letter/a/ecccb3/32.png) [@a4scody](https://community.cartalk.com/u/a4scody)\ **Post date:** [September 4, 2017, 11:13pm UTC](https://community.cartalk.com/t/car-stalling-while-idling-in-cold-weather/107537/1 "2017-09-04T23:13:05Z")
Hello, I have been driving my 1998 STS for 3 years now and have been having an issue with stalls for the last 18 months. When I pull up to stop lights occasionally the engine will stall out. This generally happens in cold weather most often. Generally if it stalls once on a drive it will then stall at nearly every stop unless I give it some gas. When it stalls, the battery and oil lights come on. Edit: A few other symptoms that I had neglected to mention: Car stutters a little right before it stalls. Drops from around 1000 RPMs to 500 then back up and then stalls. Car has only stalled once in last 4 months after not running for 10 days. This is what convinced me it had something to do with weather, as once temperatures where consistently above 50 degrees F the problem seemed to disappear. Car never stutters or stalls if the accelerator is even barely pressed I have replaced the battery and was informed it may be an alternator issue. Any help would be greatly appreciated. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [September 5, 2017, 12:20am UTC](https://community.cartalk.com/t/car-stalling-while-idling-in-cold-weather/107537/2 "2017-09-05T00:20:53Z")
The person that told you it may be an alternator issue… did he test the battery and charging system? Was he a qualified mechanic, or just a friend? Or a parts-counter (or skippy-lube) kid? Has anything else been checked and/or tested by a qualified diagnostician? Has any work been done on the vehicle just prior to the problems? It’s a 1998, 19 years old. The possibilities include but are not limited to 1 poor compression 2 worn out spark plugs 3 a bad Idle Air Controller 4 a weak fuel pump 5 a bad temp sensor 6 a vacuum leak 7 a valve problem (weak springs, bad lash, burned valves, and on and on) 8 (some) weak coil(s) (I’m not sure how your ignition system is set up) The bottom line is that someone is going to have to look at this hands-on and perform some diagnostic tests. If it were me I’d probably start with a test of the battery and charging system followed by a compression test. I’d also want to “read” the sparkplugs (they can be highly revealing), and maybe check the vacuum stability. That’s just for starters. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [September 5, 2017, 12:32am UTC](https://community.cartalk.com/t/car-stalling-while-idling-in-cold-weather/107537/3 "2017-09-05T00:32:33Z")
More than likely the problem is with Idle Air Control valve. [https://www.rockauto.com/en/moreinfo.php?pk=86746&cc=1313843&jsn=406](https://www.rockauto.com/en/moreinfo.php?pk=86746&cc=1313843&jsn=406) The IAC valve is what controls the engines’ idle whenever the accelerator is released. One way to determine if there’s a problem with IAC valve is, you’re able to prevent the engine from stalling if you slightly tip into the throttle while sitting at a stop. Tester ---
**Author:** ![a4scody](https://avatars.discourse-cdn.com/v4/letter/a/ecccb3/32.png) [@a4scody](https://community.cartalk.com/u/a4scody)\ **Post date:** [September 5, 2017, 12:44am UTC](https://community.cartalk.com/t/car-stalling-while-idling-in-cold-weather/107537/4 "2017-09-05T00:44:37Z")
The person who introduced the alternator theory is just a personal dabbler in mechanic work. So I didn’t want to jump straight to it without inquiring elsewhere. I had the battery checked and replaced by a qualified technician 9 months ago. Spark plugs have also been replaced a few months prior to that. I hadn’t taken the car back in since the battery was replaced as I haven’t had the money or time. A few other symptoms that I had neglected to mention: Car stutters a little right before it stalls. Drops from around 1000 RPMs to 500 then back up and then stalls. Car has only stalled once in last 4 months after not running for 10 days. This is what convinced me it had something to do with weather, as once temperatures where consistently above 50 degrees F the problem seemed to disappear. Car never stutters or stalls if the accelerator is even barely pressed. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [September 5, 2017, 9:47pm UTC](https://community.cartalk.com/t/car-stalling-while-idling-in-cold-weather/107537/5 "2017-09-05T21:47:19Z")
Sure sounds like and idle air control to me, too. An OEM AC Delco part is $75 on RockAuto. It could be buildup in the idle air control passages, too.