why did i lose power ? while driving.

Hello, sometimes when removing the ignition wires to replace the spark plugs, you can cause the rubber of the cables that have most certainly dry rotted over the years of use, age and heat to crack and cause spark to leak. When this happens, your ignition system may not operate as needed, causing a misfire or a situation where the engine won't run. This is a guess, of course, but comes to light as this is the work that was recently done and a relevant possible cause. A spark plug with oil on it does indicate a possible internal engine issue, but probably not enough of an issue to prevent the engine from starting. Either way, hands on testing is needed to check for ignition spark, fuel delivery, air to the intake and more. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops