Can anybody advise? I have a stock 87 buick GN with 5700 miles. Only mods are 100lb valve springs and deleted cat when installing new magnaflow exhaust. Installed new chip and let her learn before giving hard boost. 3 times I have given 80 to 90% throttle from a 20mph rolling start. She pulls great, then around 55 to 60 mph sudden cut out with a little clunk sound and feel associated with it. The engine doesnt die, no engine light comes on. I dont have scan tool and dont want one. Any ideas what is happening? Is there a boost governor of any kind? Stock injectors not enough fuel? Stock air intake not enough air? Any thoughts would be welcomed and greatly appreciated. I reached out to Eric at Turbo Tweak and he didnt have any idea what it might be. Thank you!