runs fine and starts fine every think set standard timeing exsetra running standard boost above 2half tho revs realy bad flat spot untill 5tho revs then pulls realy strong up 2 limiter and some time back fires in middle of flat spot

can anybody help
doin my m8 head in

 

Have you tried changing the fuel filter, My sister had the same problem on her 5 gt turbo and that was the fault, may be worth a look

cheers

Rich

 

mine s2 did that when i first got it so it went strait in for a new actuator and a rolling road tune and that sorted it out