Unknown SR problem, wont rev past 4k

[dustyk]

So I just started having this problem yesterday with my SR. The motor is a stock blacktop SR with a GT2871R, Z32 maf, and 555cc injectors. The car drives completely fine unless I floor it and build boost. When I do that the car starts to boost and when it hits around 4k, its almost like hitting a rev limitter. I thought it was a boost leak but my vaccum gauge reads -.75bar of vaccum which is the exact same as what I had before the problem. Just in case I checked and tightened all the intercooler piping and couplers but I still have the same problem. I definitely get a reading from the MAF, so the connection is ok. Car idles fine and drives fine around town unless I boost. It's been raining constantly for the past week, could it have something do with some sensor getting wet? Any help is appreciated

[biglipzit]

so why is ur engine reading a negative vacuum if ur under boost? shouldnt it read positive pressure cause of the boost?

[dustyk]

engines pulls vacuum at idle or when coasting

[gtune4]

make sure your o2 sensor is fully working and check all three wires, ground 12v and ecu signal