# RB25DET - Flat Spot at 3000rpm



## BlackR33 (May 12, 2006)

Hi all, I am new to the Nissan world. I recently bought an R33 Series II Skyline GTS-T.:newbie: 

I took the car for a drive, and noticed that the car hits a flat-spot in the rev range between 3000-4000rpm. Above 4000rpm, the car revs very well, and the boost guage reads about +370mm/Hg (about 7psi or 0.5bar) at full noise - which I believe is the factory setting. 

The car is stock apart from exhaust (though not sure if it is from turbo or cat back) and HKS pod filter.

I have been told that the problem could be related to faulty coil-packs or spark plugs (I will be getting 0.8mm spark plugs shortly), but I am not sure about this because the car revs ok above 4000rpm, and there is no popping noises in the exhaust which are usually associated with this.

I will be getting the car serviced soon, and I will get a dyno run done to see what the Air-Fuel Ratios and power/boost curves look like, so hopefully that might hold some answers.

If it makes any difference, the car does not have a flat spot in first gear, and I accidently filled the car up with 95RON fuel instead of higher-octane.

Any help would be appreciated. Thanks.


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## munna1 (May 9, 2006)

This is not an uncommon problem Re-gapping the spark plugs can often fix this problem so start with that. If you are still having the problem its probably due to the nissan ecu pooring to much fuel into the mix a dyno run will soon tell you. A SAFC or Power FC will fix this problem and improve power
let me know how you go 
cheers


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## BlackR33 (May 12, 2006)

munna1 said:


> This is not an uncommon problem Re-gapping the spark plugs can often fix this problem so start with that. If you are still having the problem its probably due to the nissan ecu pooring to much fuel into the mix a dyno run will soon tell you. A SAFC or Power FC will fix this problem and improve power
> let me know how you go
> cheers


Thanks Munna1, you might know me as Quinny from the Skylines Australia forum, I have worked out that the problem is the clutch.

Cheers mate.


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## munna1 (May 9, 2006)

Glad to hear you got it sorted quinny


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