just put in a new alternatar its stops running everytime i come to a stop now

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! If your 2006 F-150 dies at stops after installing a new alternator, it sounds like the charging system isn’t playing nice. The battery and engine lights are likely pointing to a charging issue. First, double-check that the alternator you installed is compatible with your truck and that all connections—especially the ground—are tight and clean. A bad alternator or a wiring issue can cause the battery to drain, leading to stalling when the engine's not spinning fast enough. Since it runs fine cold but dies warm, it might also point to the idle air control (IAC) valve. If it’s sticking or not compensating for the electrical load, the truck could stall at stops. Testing the alternator output (you want 13.5-14.5V when running) and cleaning or replacing the IAC might get you back to cruising without sudden stops. If you need any further advice or want help finding a trusted RepairPal shop in your area, please feel free to call us at 877-913-1554.