missfiring and runs strange @ 5k rpm

[ogatxx2]

hi guys, so firstly i want to pardon my bad english, im from Sweden so i will try to type so u will understand me =)

so my S14 sr20det is acting strange, i have searched the interwebz for answers several hours and i cant find a topic with the same problem as me, if u rev the car no gear or with clutch in, when u come to 5k it starts to missfire, sounds like a Bee*R almost, and this is with the throttle pushed like 2/4 or something so u rev it really slow, it also happens when u cruise in say 1st gear and rev slowly to 5k, no boost, if i have full throttle it doesnt missfire but according to my wideband gauge it goes from 11.5 to 14:0 @ 5k after 5k it drops back to high 12 low 13s, so lean i would say, or what i have been reading..

i have tested to change:
spark plugs
coilpack harness
ignitor chip
brand new Jecs 550CC injectors
coilpacks with a good known one
checked grounds and it seems good..
checked TPS
looked for vac leaks changed all vac lines
MAF is fine i guess because car dies or will go reaaaly bad with it disconnected
changed airfilter because i couldnt think of something else to change..
changed fuelfilter with a z32 one
only thing i havent checked is timing, i will do that asap when i get a strobe light, but the car runs good if u shift before 5k rpm always starts and when warm idles at 900rpm or similar..

specs on car:
AEM F/ic 6
jecs 550cc
3" exhaust
FMIC
aftermarket intake manifold and exhaust manifold
garret gt2860RS
turbosmart boostcontroller
pod filter
wahlbro 255L fuelpump
z32 fuelfilter
hks ssqv bov
54MM race radiator with two 10" fans
and with all mods on the car the car has a tune for it on dyno with 339hp and 401NM so the car is tuned.. i dont know what else to do.. please push me in a direction =) <3
sorry for long and messy post but im just trying to say everything i have done and tried

[whoareu]

huh,

just to clarify, your saying that if you slowly pull in gear with no boost at 5k rpm it will go lean...
does it do it in 2nd or 3rd also? and if your in neutral and rev to 5krpm it does that same thing? you didnt mention anything about your fpr? how is that, is it gauged?

[ogatxx2]

Yes, it does the same in 2nd gear. I have stock fpr on fuel rail and another fpr i can set The fuel pressure on with a gauge i have 3bar on idle, today i reset the timing and cas, reset timing to stock pulled cas reseted all double checked timing, i cant get The timing to be the same with tps in as I get with tps out is that normal? I set Base timing to 15 degrees without tps and when i plug it in its 25 or something, so I dont know what i do wrong

[whoareu]

im not sure man, i beleive you probably should be running an aftermarket fpr, i doubt the stock can keep up. i know with the rb25 your highly recommended to run at a minimum of the nismo unit. i would venture to say the sr's are the same. and your fuel pressure should rise 1:1 with added boost so for me the stock base fuel pressure is set at 40lbs and with 14lbs of boost im hitting 54lbs of fuel pressure. things that come to mind with your car are the tps, maf, fpr, or a dying fuel pump. but im not overly fimaliar with sr's.

[ogatxx2]

So I pulled The valve cover and set the engine to tdc and checked timing chain and it all lined up, timing chain spot on, pulled the cas and reinstalled and what not, car started fine and know it doesnt dip @ 5k at wot its 11.2 afr to redline under boost, still problem at part throttle starting to think its my aem engine management thats not working properly, thinking about to go to a shop that can do a new tune and check if that works