somethings wrong with my ls vetc

somethings wrong with my engine. the problem occurs when when you floor the gas or almost floor it, and the engine would start accelarating then just lose all power and stop accelarating. rpm stay the same. usually happens after 3500 rpm. i already changed the O2 senson, checked the timing- perfect, compression a little low in the 2 and third cylinders. im running a c/r of 11.7:1, i have a msd ignition coil with cap, and ngk iridium IX sparkplugs with nology hot wires. i know im getting a good spark but my plugs still turn black. i have prelude injectors so i know im getting enough fuel. i know my rings are good. what im not sure about is that i might have to retard the timing, or my valves are bad because they do sound like they are a little loud. sometimes i get back fire, if i take it to like 4000 rpm sometimes it would backfire. and this problem occurs only if i floor it. i can press the gas pedal a little and the rpms would go up but if i give it more gas it just looses everything. any help will be appreciated.

This may be just me, but 11:7:1 seems a lotta bit too high of compression ratio to be running on a stock ls/vtec. 11:7:1 is usually only achieved through some high-compression pistons, so you might ought to check out why it's so high. That could be your problem?

Sounds like a vacuum leak or a map sensor porblem that only happens at wot for whatever reason.

This may be just me, but 11:7:1 seems a lotta bit too high of compression ratio to be running on a stock ls/vtec. 11:7:1 is usually only achieved through some high-compression pistons, so you might ought to check out why it's so high. That could be your problem?
who said it was stock? i have srp pistons and eagle rods, je rings. all the good stuff. a stock ls/vtec would be around 9.2:1. i know that. but thanx for trying

What kind of fuel control and ecu are you using?

im not using any fuel control. might be my problem. but i have a gsr ecu with a mugen chip. but this also happens on the stock gsr ecu