Good morning. I’m currently working on a head gasket job on a 1994 4Runner with the 3.0. I’ve done one before but am by no means an auto mechanic. Everything seemed smooth until I got down to the heads and found about 1/2 quart of oil sitting on top of the block surrounding the knock sensor. The oil in the crankcase is contaminated from the blown HG, but the oil surrounding the knock sensor is not. I do know the valve cover gaskets were leaking pretty badly, but I’m not sure it would even be possible for that to be the source of the oil. Any guidance would be greatly appreciated. It may be worth noting that in the oil surrounding the knock sensor, I found a few small pieces of broken plastic. Could be from anytime in the last 30 years, I guess. The truck is new to me. Thanks.