on my st205 when i have the throttle pinned the turbo pulls hard until 4500-5000 rpm (depending on how long the engine has been running. little higher as the engine is hotter), and then i looses power and laggs hard un less i eas off the trottle, then it will slowly it start rev higher..This happens in all gears..on stock boost settings
I am thinking its a fuel shortage. i JUst changeds the fuel pres regulator but no difference and also the fuel filter.does it sound like a turbo problem to any one??or fuel shortage?

This post has been edited by dougone81: Oct 12, 2010 - 7:33 PM

fuel pump or injectors?

engine stumble at high rpm like it starving for fuel...if the fuel pump was shot wouldnt the car just not run.
-the car runs fine daily driving but cant get the high rpms.
with 1/2 throttle it will run smoother but dont get the response.

definitely a fuel shortage. Its been a long time since uve asked this question n i hope u already sorted it out. Clean ur injectors, replace ur fuel filter, verify that ur fuel pressure regulator is fine, no inversed hoses, no pressure is lost from tank to injectors...u shall b ok.