code 43 location/ intake manifold/oil

-would this be the knock sensor ,if so where exactly are they both located,my car is 93 olds 88 .looked all over online and in manual for a location pic but had no luck.
any info is appreciated

also are these 6cyl motors known to get intake manifold leaks..i have some oil(isnt all fully brown just small light brown fragments attatching to edges right now) in radiator but engine runs fine, no black smoke either(not driving till i locate source)Radiator doesnt have oil line/in ,just transmission lines/coolant hoses.

-any suggestions?

The 93 cars did not have the intake issue. Those deposits in the rad could just be glycol seperation which can feel oily. Knock sensor if it has one, should be on the lower sides of the block near the freeze plugs, one wire to them.