Q: My 97 grand marquis start but after accelerating and I let go the car will turn off or it will idle what do.you think the resaon?

Stalling in the circumstance that you are describing could be due to a faulty mass airflow sensor, faulty camshaft or crankshaft position sensors, worn spark plugs, wires or defective ignition coil(s), inadequate fuel delivery or pressure (clogged fuel filter, injectors, faulty fuel pump or pump circuit), contaminated or old gasoline, defective throttle position sensor, faulty idle air control valve, leaks in the EGR system, intake vacuum leaks, and so forth. But, based on what you are described the issue is probably "limited" and thus fairly easy to resolve. If you request an engine stalling diagnostic the responding certified mechanic will get this resolved for you promptly, and right at your location. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.