..'97 vario, there are two ports coming out of the front of the intake manifold (towards rear of car). One has a line going somewhere the other is capped. The capped line's plug is cracked and while investigating it's actually torn. i siliconed it for now but will an air leak here cause a lean condition? Can this also cause a check engine light? tia.

 

I would think that unmetered air would throw a code. Just go to any local auto parts store and find a rubber vacuum plug that'll give you a snug fit. It doesn't have to be a Porsche part. I won't tell!