I put a Moroso CAI as well as an Aluminum Intake Elbow on my '94 Z28. I knew it would run rich at first, but this was almost a month ago since I put it in. Now I'm starting to notice black soot on the back bumper above the exhaust tips.
What did I do wrong? How do I stop it?

 

I have the same Moroso CAI on my green '94 LT1 and have had no problems. I don't have the alum intake. Does it have the IAT bung? I don't see how that would make it run rich, but had to ask.
Maybe an O2 sensor is starting to fail and is totally unrelated.
SES light on?
To fix a rich condition, if nothing else is wrong, = tuning
You could put the stock intake or elbow back on see if the problem goes away. Do one at a time.

 

Yeah it has the IAT bung and I have it in. Maybe an O2 sensor idk yet. SES light is not one, I have the stock intake, but not the stock elbow. My elbow split so I junked it and got the aftermarket

 

are you sure there arent any vacuum leaks?

 

^Idk where one would happen...I put everything back right. I've taken the OEM airbox/elbow out before and put it back in with no problem.