hi guys
v5 sti (which was rebuilt with new forged pistons and stronger rods from the newer impreza's )
harveys fmic
3" full decat
k&n
and a simtek ecu with als and lc
dynoed at 336 bhp

car drives mint and really powerful in 2nd, 3rd, 4th and 5th! and pulls cleanly with no hesitation

But in first gear when you nail it, it aggressively cuts boost to nil! like ahitting a brick wall but slowly running through first it is fine
it feels like fuel starvation but i dont know , i get no warning codes at all , no smoke nothing and barring this it runs perfectly

what would cause this?
is it my pump as its standard or is degredation of the coil pack

it boosts at between 1.4 an 1.5 bar depending on how it feels!

 

I assume you have a Walbro GS341, 255 lph pump.
Have a word with your Simtek mapper.
Regards,
Harvey.