i was on my way home tonight, and i started to hear a weird tick, and it wasnt consistant. so i slowed down and it stoped. i continued my drive home, and when i got into my driveway i heard the tick again, and then all of a sudden it started to sound like firecrackers where under my hood. i turned the truck off and when i started it back up it was the same sound. it sound like lound poping, and i can see air moving around the drivers side head around the spark plugs. its sound more like an exhaust problem, but i wasnt sure if it was a spark plug blowout. let me know please