engine light ⚠ warning comes on in heavy traffic either by stepping on the brakes or shifting from drive to park

When in heavy traffic either by stepping on the brakes or shifting from drive to parking the engine light comes on and locks/disengages the gears and the accelerator goes dead and the car simply rolls. When you switch off the engine and ignite again it clears. But it has become too persistent and it lights prior to ignition and immediately after and when you switch from parking to drive the car jerks as in shakes, but the accelerator stays dead.