EZGO98

I finally got a couple of days off, I got the intercooler repaired, put back in and drove the truck it would now make some boost if I would get on or pull a little grade, but not over 17 psi and egt's shoot up quick, so yesterday I put the boost leak tester back on and pressured it up to close to 30psi but it kept blowing the leak tester cap off, so I am sure it is pressuring up and if it has a leak it can not be very big, what else would cause very low boost and high egt's :confused: