What's limts the boost on a standard map? As some times my car is fine some times it runs at 0.6 bar and it's ok , sometimes it's 0.4 bar and it's stupidly quick and sometimes it keeps going to 0.9 bar and runs like a snail?

It's got a fmic, cat back system, 2.2 airbox, dumpvalve, rbs bypassed, precat decat, new map and front boost sensor, actuator only on 4 threads