1G Stumble's in third

[qwkdsm2]

Need help guys. When I get on it hard, all gears, first and second pull great to redline but when you drop it in third and RPMs get to about 4500 or so it'll stumble. Motor doesn't shut off or anything. Same thing happens when I'm doing 70MPH dump it in third and floor it, it'll stumble. All other gears are fine though.

Is it fuel cut? I'm running 19-20psi on a ported/clipped 16g with 450cc injectors.

I have a 190lph pump, 6an line from tank to rail, SX fuel filter, FPR.
I have RC 550cc injectors but haven't put them in yet.

Other mods
FMIC
3inch turboback
38mm Tial wastegate
2g manifold
What could be causing this?

 

[CanadianTSi]

Could be fuel cut, but fuel cut is more violent then just a "stumble"

Check your Plugs and Wires.

 

[blcknspo0ln]

Could be fuel cut, but fuel cut is more violent then just a "stumble"

Check your Plugs and Wires.

and of course for your inherent boost leak

 

[qwkdsm2]

A boost leak can cause that? My psi never drops on the boost gauge.