i own a sierra rs cosworth stage 1(chip-31 actuator-GGR exhaust 3'' full system)
the boost is set to 1 bar, but the last 2 days i noticed that the pressure not exceed 0.7 bar,when i press the pedal to the floor
i check the boost hoses ,its ok
can you give me any solutions?is it the outside temprature(now the weather in Greece is to hot)
is it the actuator?is it necessary to reset the ecu?(and how i will do that?)

 

Can you test the car in the early morning to see if it then makes 1 bar ?

You will always see the performance drop off on a Cossie, when the outside temperature goes up

To try and offset hotter air temps, you may need to consider fitting a bigger intercooler aswell as water injection etc.

With regards to your actuator, well the spring may have gone weak. In which case you will need to swop it over to find out. (make sure you get a Genuine Garrett -31)

 

i make the test early morning!!!!!!and the boost pressure not rise(stable at 0.7)
i have never had this problem before(also summer period)
before one week my car runs ok(fly)

 

ok.

Well first check to ensure that you dont have any air leaks and then switch the actuator over.