Could it be Fuel cut?

[luke 3mps]

When driving along in any gear put the foot flat everythings fine. starting in 1 or 2 put in through the gears changing at 6000rpm after the second gear change, it starts to surge ( power off and on not jerky a soft surge).. usually 4 sometimes 3

Any thoughts? fixes?

[AD07]

Sounds like it could be fuel cut mate....im sure ive heard of others having this problem. Investing in a Dash hawk will give you fuel pump pressure. Maybe take it back to where it was dynoed & see what they think.

Good luck.

[Jmac]

Yep, borrow or buy a dashhawk.
Either that or it could be KR (Knock Retard).

[luke 3mps]

OK thanks, how to cure it?!

[AD07]

Might need a new fuel pump (or upgraded internals) or maybe a tune to streamline all your mods.

[Jmac]

Just realised you have aftermarket turbo?
Most likely boost cut...
Have you got a boost gauge? What area are you from? Maybe someone can hook up their DH and do some logs.

Id say most likely a tune as AD07 said - but without some logs its pretty hard to tell.

[Doc]

check all your clamps...

it may be boost cutting if your spiking above 18ish

but try step one first

then get a dashhawk .. no questions.. just get one

[Doug_MPS6]

6000 rpm??

[luke 3mps]

between 4000-6000rpm

[Doug_MPS6]

If its happening well up in the rpm register it could be the ECU timing settings moving progressively towards retard as an engine protection measure, possibly along with those other items (fuel and boost cuts) already referred to. A DH or boost guage will help you see if there are boost spikes. Do you have a stock ECU or a Standback or similar? If the latter, how is it set-up, especially wrt ignition timing and specifically wrt your aggressive (?) boost settings? This comes back to a retune to align all the mod's as suggested above.