Hitting The Wall After 6000Rpm At Wot?

[zoom]

Hi Guys & girls,

need all your helps please.

car: r33 gtst

Car has just rebuilt and run in. Have started to tune and it was running fine (7500rpm) with 25psi for a few hundreds km. Recently experiencing something like misfire which almost like hitting the rev limiter at about 6000rpm+ at 15psi or even at 12psi. Initially it was intermittent but now it is all the times.

some of the parts are:

new split fire

copper plugs with 1.1mm gap running HKS twin power ignition

PFC

GTX3071r

forge internal

metal jack balancer

June oil pumps

etc.

Things that i have eliminated: running 15psi

1.gap the plugs to 0.8 - problem still persisted

2.removed hks twin power and replaced with my stock harness - problem still persisted

3.Replace all split fire to stock coil packs - problem still persisted

4.Checked all vacuum hose - all good

5.fuel pump is ok. fuel pressure 44psi, and 54psi at idle, 60+psi when under load.

6.Datalogged the a:f ratio stays at 11.8. so injectors and pump should be ok?

Since it is only happens from 6000rpm and not from 4500rpm, I believe it is electrical issues and not the typical misfire that many people experienced.

Is it possible than the ECU ground not connected properly?

Where about can i fine it? Should it be clamped to the cylinder block?

All your helps would be appreciated.

[STATUS]

check the ECU male plug has not bannana'd when it was done up, the far ends sometimes dont seat only the middle and it can cause a missfire.

[zoom]

thanks Trent, will check it tonight.

Just a thought, why is it just doing it now and not intially for a few hundreds km?

Tried this morning again, have also noticed that as long as it is on boost (8psi) half throttle it also have the same problem!