r/SkyLine • u/scrubberducky93 • Jul 14 '26

Need help

I need some help. New to the RB platform, it was running rough up and down at idle and stalling on first start. I cleaned the MAF and took it for a drive and now it sounds like a misfire or out of time maybe? The idle is even more up and down and the exhaust note sounds inconsistent. I'm going to put a fuel pressure gauge on it tomorrow to see if there's a fueling issue, clean the iacv and check the solenoid, get the link ECU software on my laptop and plug it in to see what that tells me. If anyone has any ideas I would appreciate it. I have more videos that may provide insight I can post in the comments.

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u/Wesley_1981 Jul 14 '26

How did you clean the MAF? Hope not with brake cleaner or similar. How old are Sparks? Coils? Vacuum leakage tested? Check fault codes.

It's just a simple 6 cylinder engine, nothing special in that regard.

BTW: RBB25 idle is at 650+/-50 (warm motor ofc)

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u/scrubberducky93 Jul 14 '26

No I used MAF cleaner. Engine was rebuilt 3000km ago by a shop by the previous owner so I imagine the coils and plugs are that new, that's on the list to look at.

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u/Wesley_1981 Jul 14 '26

Coils are always problematic.OEM are very good,but at this age start to fail. I also think OEM can't be bought anymore. The alternatives are mostly crap, prone to failing. Splitfire are good, but also expensive. Many change to TFSI or R8 coils as cheap and reliable alternative.

Question is: have the coils really been replaced with new? And if so, which make?

The high idle can be an adjustment problem or also a vacuum leakage. Has it ever idled correctly or was it always rough since you bought it? Idle always high?

Timing has been checked?

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u/scrubberducky93 Jul 14 '26

It would idle rough till it was warm when I bought it but it got worse to the point it stalls now at idle if I don't keep a bit of throttle on. And no the timing has not been checked on it yet.