VY SS missing at/over 3500rpm

[calobes]

Hey guys,

So my vy ss has a miss at 3500rpm wot, worse when it's not 100% heated up. Most noticeable in 2nd probably because that's when I'm at 3500rpm wot most often. Had my mechanic look over it and he can't find a thing. Earth points all good, no codes etc. He pretty much told me it has to be the tune.

It started happening when I installed a full exhaust, otr and mafless tune (all at once).

I have replaced spark plugs and leads, and tested the car with a mates coil packs with no improvement.

Now the tuner confidently said he guarantees it's not the tune and will take it back to stock tune to prove it. I am doing this tomorrow.

So if its not the tune does anyone have any idea what it could be?

I can't find a fault exactly like mine when I search so really need some help, it's really starting to do my head in as I want it track ready.

Thanks

 

[SS-REX]

Hows the o2 sensors? did you replace them or are they still stock?.

 

[calobes]

I haven't replaced them, chances are they are stock but I'm pretty sure he bypassed them with the tune.
They didn't throw any codes

 

[calobes]

So it's officially not the tune. I am the proud owner of an untraceable misfire. Not really sure where to go from here, two mechanics, auto sparky and tuner have no idea.

 

[dat111]

can you change it back to stock tune? if you can, try that i had a mate with a skyline that was missing at 4000 revs and he pretty much changed everything on his car that he could. to find out that it was actually the computer was fryed

 

[chriso-k]

A miss, you say? That don't tell me much. Describe your definition of a miss?

 

[XUV]

Does it push beyond 3500rpm ? as this would be around 175kph in top,, if it dosn't maybe the limiters be changed.

but from reading alot on hear, O2 sensors seem to cause the unexplainable, as they don't seem to throw codes when they're on the decline.
So spend a $100 and change them.