when one or two pistons fire a little late and you hear little popping sounds in the motor, i cant remember what this is called but my explorer is doin this when i climb a hill. does anyone know the direct cause of this?my moms old station wagon used to do this alot and when i learned about while workin in a shop i immediatly identified it.........but now i cant remember what its called

 

Hi, I think you are referring to pinging, also call pre-ignition. This happen whenthe enginefires when the piston is not all the way up. It happen when the engine is under a load, likegoing up an hill.

Nic.