1988 Holden Calais VL review from Australia and New Zealand

Has blown black smoke since I got it, once the engine reaches about 3000rpm, it gets too rich and has trouble accelerating any further and black smoke billows out the exhaust until I back off. Had it fully checked out by a mechanic, he changed everything including injectors, computer, airflow meter and oxygen sensor trying to find the problem. He finally got the mixtures right on the dyno, but after a week of having it back it's beginning to happen again.

Could someone please help me, I don't know what the hell is going on. He suggested it could also be the charcoal canister, maybe filling up with fuel and being drawn back into the engine at high RPM.

It's a beautiful car but I am getting very frustrated, apparently the last owner sold it because he could fix it (nice of him to tell me before I bought it, not). But for the week it went well it was fantastic and was producing 100kw at the wheels.