Evening people! Right! now that i'm bored with getting pissed constantly decided to have a look at fixing my car for the summer!

Basically 5k and it starts missing! change gear and it momenterilly fires on three for a second or two til it clears and it hits 5k and it misses again! Altho after cruising at say 50 mph in 5th for 5minutes then dropping it to third and giving it full throttle it will pull to the limiter without missing at all!

So far have tried....

Leads
rotor arm
distributor cap
2 sets of plugs 3 different gaps!(902's NGK 9's at .5 .6 .7mm)
coil (and power feed to coil!)
ignition amp
Water temp sensor(runs at 87degs)
Thermostat
Charge air sensor(runs at approx 22degs)
crank, phase, map sensors(all tried with direct feed to ECU)
different ECU's (p8 and L8)
different Chip (2 no. 1 blues chip 1 grey chip)
different Injectors
No faults showing up on Pectel monitor during miss fire!
Block tested for leaks(also ran without water cooling on turbo and no pressure cap still missed as bad)
Fuel pressure is fine all the way up!
The intake pipe to the compreeor housing is 3mm Stainless steel so that aint collapsing!
Boost pressure seems to have no effect on it(stil misses at 20 psi like 32psi)
There are no multiplugs on the inner wings been replaced!
and all the connectors are lubed up!

Any idea's people?