Volvo: fault code, fuel pressure regulators, mass air flow sensor

Question
do you think its the mass air flow sensor  thanks
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-----Question-----
i have a volvo 2.3 c70 t5 coupe 1999 model
the fault code is P1171 HOPE U CAN HELP THANKS
-----Answer-----
Mick,
Long term fuel trim.
ondition
The control module receives information from the heated oxygen sensor (HO2S) about the fuel/air mixture when idling at both the lower and upper part-load range - If the fuel/air mixture deviates from [lambda]=1 the short-term fuel trim will compensate for this by adjusting injection time so that [lambda]=1 is achieved. When the short-term fuel trim makes an adjustment, the integrator median must be adjusted by the long-term trim. Diagnostic trouble code (DTC) ECM-261A P1171 will be stored when the long-term trim must be adjusted to maximum in the lower part of the load area.

Upper limit:
intake air leakage
exhaust system air leakage
low fuel pressure

Lower limit:
intake air leakage
high fuel pressure
leaking injectors
defective mass air flow (MAF) sensor
contaminated engine oil
oil level too high  

Answer
Mick,
There is a very strong possibility that the Air Mass is the fault, yes. I have replaced many, but also have found many vacuum lines to be old and cracked causing vacuum leaks. The fuel pressure is also very much a possibility, fuel pressure regulators go bad.