I replaced the spark plugs with ones ‘recommended’ for my vehicle by an auto store (NGK iridium ones). The check engine light has not come on for about a year (and when it did, it was the catalytic converter going weak). Check engine light turned off and has stayed off for a year or so - but the catalytic converters have not been replaced. The engine only stalls while idling or in very low gears. It easily starts again but will die when shifted to reverse or drive. It does seem that when I drove it faster, it wouldn’t stall. Also, when I turn on the car, it makes a very loud spinning/clicking sound that seems to be coming from the right area of the engine - But ONLY after I have shifted into reverse or drive. I know also that there is minor oil seepage coming from the valve cover gasket. I will try the gas cap trick. Thanks for your help!!!