Volvo 850 power loss under hard acceleration Topic is solved

[Jaumme]

Thank you clemens i will

[Jaumme]

I feel like boost goles Up ando then goles down a bit And remains a bit low, what can cause this?

[Jaumme]

I think my tcv is leaking a bit

[Cookeh]

Boost leak would cause that sort of thing. TCV is a good place to start, as you said. Also check the vac lines on the turbo housings - I had two split here just last month.

[erikv11]

Other very common causes of boost leak:
- the 20 year old hose on the IAC is cracked somewhere in it
- the 20 year old CBV diaphragm has hit the end of the road, too many flexes, look for actual holes (can see light through it) or lots of cracks where it flexes. Can be tested with a vacuum tester / brake bleeder.
- Intercooler path. So many hose/pipe junctions.

[Jaumme]

i did check all of that everything is ok, nothing leaking.
the boost is half way the white line every time till 5500 rpm then goes 3/4 white line.