Missing Between 4200 And 6000rpm..

[Doze]

As the title states.... under load car starts missing around 4200 through to 6k and then revs through fine.... no engine mods done, (that I'm aware of), pretty much always been ultimate fuel (bp is at end of street) on my r34. Any ideas from past experiences...

[RaBBiT001]

From past experiances i had no mods pretty much but regapping the spark plugs fixed it. Everyone will tell you it will be spark plugs which needs to be regapped to .8 or they will say it could be your coil packs. But to start if i was you i would get the spark plugs regapped or just some new ones that are already gapped to that as after market coil packs are expensive and you might not need them.

[Doze]

ah shoulda added.... plugs aren't too old, about 4000kms, iridium's gapped smaller than standards to around 0.95 from memory

[32JEZ]

afm, coil packs, fuel filter? any of those.. mine ended up being afm.. and partly coilpacks.. just got it fixed.. but yeah exactly the same as me, and it just gradually just got worse.. gl

[Doze]

Jesse, did urs come and go?

Reason why I ask, I went to work this morning and it did it barely, and then nothing, was fine every time I went into that range under load....

[subzeroR33]

I would say its your plugs, go and buy some cheap copper plugs NKG BKR6E and see what happens.

I dont think you should be gapping irridium plugs i have heard it f**ks them up.

[Revhead]

A search should bring up heaps of results...

This is generally a coilpack issue, using different plugs (BCPR6ES coppers in my case in my old 33) and gapping them to 0.8mm might help but you're masking the root cause of the issue, which is a weak spark. A set of Splitfires or similar should solve it, but maybe see if someone will swap coils with you to test it out first?

[32JEZ]

yeah bud,

dude it was very random!! it was a flamin mongrel. cos i had nfi wat was wrong went to take it to gavin wood and OF COURSE it ran fine .. then on the way home started again so funny but yeah hated it.. 1 day or morning it will be ok.. then on the way home terrible >_<ect so forth lol.. for me i changed afm and got new splitfires/plugs.. but yeah i did trouble shoot first.. trying the cheaper stuff first.. like fuel filter.. did nothing then i changed plugs.. nothing then swapped afm and bought new coilpacks as they were on the way out too.. worked a treat

[Doze]

Thanks for all the replies... I tried a search in forced induction, but kinda came up with a lot of stuff I didn't want as well, some of the ones I looked at were same or similar things to do. Coming up to another service so will end up with a major tune once I find a good shop on the northside and see how it all ends up.

[chef_stagea]

spark plugs or coil packs.. happend in my stagea... i F&cked off the neo cover to keep it a little colder.. didnt think it would so ne thint but it did!