MAF sensor changed but car still have no power when driving it.

[misha]

Does the car have 2 o2 sensors or just one?
Where is the hole in the exhaust....before front o2 sensor or between 2 of them(if there is one after a cat)?
Check for vacuum leaks....they kill performance on turbo cars.
Check the fuel pressure regulator and fuel pressure.
Check ribbed hose from maf to intake.
Spark plugs MUST be irridium ones for T5 or oem Volvo ones...or cheap copper ones BUT properly gapped because gap is CRITICAL on these.
Did a replacement MAF had the same BOSCH # number like old one?
What is the condition of turbo?
Make sure that intercooler doesn't have a hole in it somewhere.
Are there any codes....is check engine light on?
On '95 you can read them yourself from ports under the hood.

[Klausc]

All Volvo turbos have intercoolers, they cool the intake air. If the intercooler has a hole in it, it has to be replaced. This can be because a rock hit it - the intercooler is in front of the radiator and AC condenser and is visible behind the front grill.
Usually, the intercooler piping in the engine bay gets loosened by a mechanic and the same lack of power exists. Lift the bonnet and check all of the large black tubing connections. Using a rag, grab an air tube and try to twist it. If the tubing moves even a little bit, tighten the clamp with a screwdriver.