Dead Rev Range 4000-5000rpm

[Brent]

Hi guys, so I'm having this problem where the car makes barely any power from 4000-5000rpm. I'm not being paranoid, it's very noticable. It picks up again after 5000.

It's an R34 with RB25DE. It's only been happening since I changed the spark plugs (NGK Platinum), Coilpacks, oil (Castrol Magnatec 10-40W), oil filter and fuel filter.

I changed them all at once, because I thought it would be nice to give it a bit of a proper service.

What could be the problem?

Oh, a few things to add: It doesn't misfire, fuel filter is correct way, and spark plugs are 1.1mm gap (correct I believe).

Cheers, Brent.

Edited April 8, 2010 by Brent

[Aggroman]

check the butterfly valve on the the throttle body is opening properly and not getting jammed..

That could be the problem as the VCT is supposed ot kick in at around 4000-4500 from memory.

If not disconnect the positive (I think) side of the battery and drain all the charge to do a reset of the CPU and see if it does it after that.

Hope that helps.

David

edit: oh yeah is it auto or manual? if its auto its probably cause autos suck haha just busting your balls, But if it is auto it could be something else..

Similar stuff has been covered before so have a search in this section something like 'lack of power' or 'sluggish'

[Brent]

Car is manual.

[noely1]

bro mine does the same at about 5,500 revs it really really takes off but anything below especially 4000rpm range is very sluggish.. i recently changeed to splitfires, got a 100k service etc new timing belt and it sounds like air gushing out really fast in high revs... like im losing compression somewhere

it's really annoying aye? but i got mine converted from an auto - manual and am still on the auto ecu... so i dunno if thats my prob or not :S

[N-DAWG]

Also check that the vacuum line from the airbox to the butterfly valve solenoid isn't blocked off if you have fitted a pod filter. in general check the vacuum gallery. I posted in a thread somewhere on here a diagram, i'll see if I can find it later, but that has also been known to have similar symptoms if it is blocked.

[N-DAWG]

http://www.skylinesaustralia.com/forums/R3...;hl=vacuum+line

There's the diagrams

[666DAN]

Also check that the vacuum line from the airbox to the butterfly valve solenoid isn't blocked off if you have fitted a pod filter. in general check the vacuum gallery. I posted in a thread somewhere on here a diagram, i'll see if I can find it later, but that has also been known to have similar symptoms if it is blocked.

+1 Seen this many times, some clown did this to my car when they put a pod filter in when I bought it....was amazed the car went from acceptable to pus performance.

[Brent]

Thanks guys, problem fixed!! It was the two vacuum lines for the variable intake control solenoid. (10 and 3 on the diagram). They were switched around, this was my fault! Thanks guys for the help, and diagram

-Brent.

[N-DAWG]

No worries mate, glad I could help