boost problem

[Vovan]

When using a boost at 0.9 my car suddenly stops boosting at 6500 revs (boost goes to vacuum, i see it on my stock boost gauge). It looks like it's a knock sensor cut, but i'm not sure. If using stock boost - everything is ok. I've tried to make fuel mixture richer and leaner, but it didn't help. When i drive with a hood little opened - looks like everything is ok. I thought it is bad oil (had same problem before and oil change fixed it), but after changing this stuff happens again. Looks like the incoming air is too hot and causing the detonation.. can this be a problem?

[rb25]

are you using the stock ECU?

[Vovan]

yes

[Vovan]

i think i've found what the problem is. It's the detonation - the ECU collects the info on detonation and when it thinks there were too much of detonation it just cuts off on high RPMs. The problem is solved when i reset the ECU, but it helps for only 30 minutes. After that the problem appears again. I'm not sure what is happenning, because i don't feel that the mixture highly detonates