2jzgte miss at 5500 rpm pls help

[montzz]

hello all
have a problem with my aristo v300 2jzgte auto ,its totally standard ..it starts perfectly runs smooth up until 5500/6000 rpm where it seems to miss or hessitate and if you keep your foot down it will struggle but will then rev right round to 7/8k
it seems to just hit a wall or like the rev limiter for a few seconds
i put in new plugs ngk r and gapped them to 0.7 but still the same
it will do it no matter if driving or sitting still in park or neutral no matter if you floor it quick or try to gently press gas pedal
ALSO when it hits this 5500rpm problem the engine light comes on then goes off
things im thinking of could be ,,coil pack leads? fuel pump? blocked catalitic converter? yes still has them on lol i wanted to get it running perfect before i start to modify it bit by bit ,

i tried to get the codes from the diagnostic port by joining the tc and e1 or whatever the two was to connect as my diagnostic port doesnt have connection in the tc1 as its a vvti but this just made nearly all the lights on the dash start flashing like an xmas tree ,,i did read if youve an immobiliser it can **** up diagnostic??? an i do have immobiliser
anyone else came up against this or any knowlage on it will be greatly appreciated