I has to be a flow issue, if the wastegate can't open the only thing that can stop the turbo from spooling till it throws a rod is either not enough air getting in or not enough air flowing through the exhaust turbine. We've eliminated the cat (it's now hollow) it's not the air filter, the cooler isn't blocked and there's no leaks. Steve mentioned that the exhaust cam timing could be stuck hence doing something with the valves but that's where my knowledge kinda stops lol Going to check the exhaust flow this arvo and hook the boost gauge up to the turbo to see what boost its actually making