Hello, I will be glad if you can help. As the weather is getting colder, I see a decrease in my turbo pressure again. I don't have such a problem in hot summers. I feel power loss below +15 degrees. When I look at the turbo pressure gauge, it shows 0.5 bar pressure, but when the air is hot, my pressure is 0.8 0.9 bar. I wonder what is my problem, it does not show a fault in the diagnostic device. I have no problem with my ect thermostat, it's new. maf sensor, my oxygen sensors are new. I replaced the Iat sensors, the car interior temperature sensor and the sensors that measure the air temperature in the brain, but nothing noticed, I was hopeful for them, but my problem did not improve.my car is s70 t5 98 model manual

 

there will be some change in the calculation for fuel trim (air/fuel ratio) due to the cold temps creating denser air. Not sure if its all the way down to .5 bar but I'm wondering if the MAP sensor could be in play. The difference in air density from a warm day (ie 75F to a cold day say 20F is about 10-12% so that would be reflected in the boost change (ie .8 bar going to .7 bar...)

 

thanks I will try the Map sensor.