hey guys

I have a 1990 z24 with an exhaust problem I have failed two e-tests but the results
are just outrageous. I have done a complete tune up and I replaced the o2 sensor and the muffler before doing the emmision tests but I keep getting a grey smoke from the exhaust followed by a rather harsh smell after giving it some gas. but all in all the car runs great.

can anyone help me with this problem?

could a faulty idle air control valve cause this type of issue with my exhaust system?

sounds like a bad coolant temp sensor that gives the ecu the temp signal