Say my car is starting to develop some issue, yet it's not clear at all what the issue is. Say we can hear some light knocking sound in the engine. That could be quite a few things and mechanics say it's too early to diagnose the thing. We just need to wait until the thing is clear enough. In Polish mechanics often say what translates into "Drive and watch" or "Drive and observe", meaning you just keep using your car and be more alert/vigilant as for the issue, whether it's worsening or not. Would that phrase work? What would English say?