I'm having power issues with my st170 but carn't find the problem. I have changed the cam and crank senser's , injector rail , fuel pump , coil and leads and had a new exhaust system but it is still the same. It starts dieing out at 4000rpm and chuging round like there no fuel gettin to it. Be greatfull for any feed back.

Lambda sensors or air filter?

get the furl lines checked to see if enough fuel is getitng through first.. eliminate that first

i was gonna say fuel filter... check for clogging...