hey all i've been looking for this problem for about the last month now its starting to get to me!
the car
ae86 with 4age 20v silvertop
i've wired in a lt10s microtech with the x4 coils. Cas, tps, vvt and water temp only wired in

It all started about a month ago when i finally got my car registered, i drove it to work and it would only rev to about 4000 rpm with no power! and if i stabbed the accelerator hard it would die. that afternoon i took it to the tuner , but as we were driving it he played around and said somethings not right! ( obviously) at this point it was throwing rpm errors on the microtech and about 2 streets later i lost all power and limped home at 20kph. To add to this exhaust was that hot it started melting my starter motor wires. the next day it wouldn't even run, that brings us to now where i've spent a few weeks trying to locate the problem. I'm hoping one of you guys have had something similar and can put me on the right track!

this is what i've checked / done
replaced spark plugs
replaced fuel filter
replaced the 4 microtech x4 wires coming from the lt10 to the x4 cause they have strands of wire broken
added in an extra earth on the lt10s and earthed the x4 to the engine block
Got the cas tested - fine
got the microtech ecu and x4 box tested - fine
injectors ultrasonic cleaned
fuel pressure is 42 psi @ 2.5l per minute
tested ignitions leads no more that 6k of ohms and there a foot long each
put a noide light on each injector to check to see if injectors had power, also put microtech into test mode and checked all 4 cyls for spark - fine
removed x4 and coil pack harness and looked at all wiring and resistances - fine
* i did however come across a startling discovery when i removed my tappet cover to find one of cyl 2 exhaust valve was stuck open fully. after removing my exhaust cam and luckily freeing up the valve i was sure that is was my problem! but nope still no better.
i had also checked valve timing and compression after fixing the stuck valve - 180 over all pots

i am honestly out of ideas! any input would be great i'll even recheck whatever people might think is wrong with it. i will try to post up a video of how it runs, it literally runs on 1 cyl @ full throttle - 500 rpm.

cheers twisty