Q: Lincoln LS cranks but won't start. Checked fuel pump fuses/relay, all good changed ckp sensor, it started once. Now it won't

Measure fuel pressure on the fuel rail. If the pump turns on, that’s hopeful but it doesn’t mean there is actual pressure. Also, check for actual injector operation using a noid light. Is there an actual spark at the spark plugs? If the injectors are delivering fuel and there is a spark, other items to check are the coolant temperature switch, which must be functioning properly at cold start, and cylinder compression and air induction. If you want the required diagnostic steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a no start diagnostic and the responding mechanic will get this resolved quickly. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.