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Hey guys and gals,

About 9 months i got my baby, 1 of 2 dream cars, an r33 gtr (others a ford gt40... yeah i kow i can dream) :) anywho after a couple of months i found that she'd misfire at around 5k under max boost at stock, so after savng abit i took her to c-red and forked out abit for a haltech cpu and tune and it seemed to fix it, turns out it was missing the air filter plug thing and only one of my 02 sensors was working... Feeling confident i was fixed they bumped it up to 14psi on stock turbos and a remap. Dyno'd at 340 atrw:)

Noticed around a couple of months later that she was doing it agan, 5k under boost, mainly 2/3rd gear, nice jerk:( did a bit of study and found that the coilpacks can be a good cause of the problem, so i bit the bullet and got the mighty splitfres, cant go cheap on these beasts:D

Anyway today after the install drivin down row, changed from first to second, hit 5k again and to my dismay she jerked... WTF could it be, and it always seems to be at the 5k mark...

Things runnin through my mind:

- spark plug gaps

- too much boost on stock turbos

- too much exhaust gas for the stock exhaust...

Does anyone have any experience in fixing this and co0uld possibly point me in the right direction??

Edited by gunns
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an r33 gtr (others a ford gt40... yeah i kow i can dream)
Feeling confident i was fixed they bumped it up to 14psi on stock turbos and a remap. Dyno'd at 340 atrw;)

Rears? or alls? :) ..... GTR .....

I'll assume you've read this.

What kind of "jerk", like missfire, or like, broken nose over the steering wheel, blood pissing out everywhere, and call your mother because tears are running down your face ??

Could be a bad alty (only ever had one in all my cars, started hessitating occasionally a higher rpms, then more frequently, then at lower rpms, then finally gave in)

Could be alot of things, just depends on what exactly is happening at that 5k RPM mark, could be crank angle sensor, air, fuel, spark, ECU

ah at the rears, c-red have only got a rwd dyno.

Haha jerk as in missfire, bout a split second of nothing then it picks up again and keeps goin good right up to 8k with no probs. i have yet to have any problems below or above 5k, seems to be very specific. i get the spark plugs changed every service, 5-10k's so i can cross them off. i just read another thread similar to this (gotta love the search functon) where they were mentionin the wiring loom. I might give the mechs a ring tomoz and see what they think, but i think a loom might be the next on the hit list.

Ta for the quick reply

Wiring looms from the ignitor box to the coil packs is a common fault, because they're inside the valley cover and prone to heat. They usually run OK until you try to move them and they go crunch, then they're f**ked. Same with the ignitor box itself, sitting on top of the cover doesnt help a great deal, alot of people mount them onto the firewall.

Couldnt find any wreckers around my work in Welshpool that had any for me because theyre such a common f**kup, you can order them from JustJap, SlidingPerformance, maybe eBay, etc... or let a mechanic stretch your ass for it.

Wicked as, so from the sounds of it, wiring loom or ignitor box, or cas if im unlucky. im not mech savy so unforunatley so wont be able to checkthis for myself, sounds like ass stratching FTL :-(

I guess itwas a bit noob to think that going splitfires woud the ducks nuts and just magcally fix it

Im just over in Swan View if you ever need a helping hand mate.

Splitfires might be a setback now, but when the problem is fixed, you'll notice a difference for sure.

Ignitor box will be cheap as, wreckers might have an ignition loom (they do, just as soon as they arrive they sometimes sell out quickly), and theyre pretty cheap too.

Does anyone have any experience in fixing this and co0uld possibly point me in the right direction??

Fixing what ?? Most replys here are just wild stab in the dark .. go look in the workshop thread and visit the 1 closest to you

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