[311evo]

boost leak test would test the pressure the intercooler piping could hold, compression test it a closed combustion chamber between the piston and head, basically to test valve seals or possibly gasket. if you had a boost leak it would throw off the signal when you go under load, and start trying to build boost. otherwise timing could be an issue, but that WOULD possibly show up on a compression test because the valves would not be sealed at that point, but for it to jump that much, idk, might be unlikely.