... My gas saver for work and travel when moving large items isn't needed. No issues in 3 years of owning. Then, enroute to work one morning, she starts to misfire, about miles from home. Doing a steady 55 mph, kind of felt like it dropped a cylinder or 2. Okay, I was half way to work, so I kept going. I went to Auto zone after work, codes said coil pack 1 and 2, okay, fair enough, sounded right. I needed to finish a phone call for business, so I sat in the car, running, with the A/C on, it was hot out. After 15 minutes, the car died. Odd. After that, it wouldn't start again. That's where I'm… Lire en entier

**Vehicle:** 2019 Lincoln MKZ AWD

**Issue:** The engine temperature rises when the car is idling for more than 10–15 minutes with the AC on. However, the temperature stays normal while driving at higher speeds.
**Work already done:**
- Replaced the thermostat
- Replaced the water pump
- New battery installed
- Radiator fans are working
- No coolant leaks
- Tried bleeding the cooling system (air removal)

Despite all this, the problem still happens at idle. The coolant reservoir was left open temporarily during bleeding. Could this have caused air to enter again? Also, could a partially clogged radiator or bad head gasket be the reason?

Any advice or similar experiences would be appreciated!

Car is stalling at idle speed