I'm using a Tial 38mm wastegate. It's been on the car for about 7-8 years. Also using a turbonetics manual boost controller. When the wastegate opens to controller boost the boost gauge flutters badly. It only does this when the wastegate opens. Doesn't matter where the boost is set at. I have had it on my 2.2 that I had recently pulled apart to freshen up, but found severe valve guide wear. Thought that what was causing the problem. I have now swapped to a 2.4 using the same wastegate and the problem is still there. Anyone seen this issue?