97 a4 1.8t quat. I had serious bucking and jerkin when the turbo kicked on...replaced all vac lines, n75 solenoid, pcv.... Smoke tested and no more leaks. Now no turbo at all! MAF is fine,ECU is good. Mechanic lookin at it tryin 2 troubleshoot for weeks. Now today oil started spraying out of the compression fitting on the oil tube goin into the turbo?! The brass nut is tight and no visible cracks. Could this whole problem have started because of oil sludge? The oil temp gauge also never goes up