I have a 2001 with 155.000 miles. It is blowing excessive black smoke and has had a PO234 code for overboost. Running down the highway at 70-72 with the cruise set it will blow smoke every time the boost goes above 10 psi. I had a couple of holes in the drivers side intercooler tube welded up just before the code started. I am trying to check my waste gate actuator. When I applied about 30 psi shop air I couldn't hear any air leaks but it took about 40 psi to move the rod. The waste gate arm only moved about 3/8". Is this all that it should move? I suspct that I might have multiple issues, possible some bad injectors also. Any help would be greatly apprciated
Tom