i believe it's a temperature dependant problem
I have a 91 volvo 940 turbo with an automatic. When I'm at wide open throttle and the rpms get to around 4000 to 4500 it's like the rpm's start fluctuating and it starts kicking. The boost gauge flutters up and down and the rpms drop and jump. It seems temperature related. Last few days it's been in the 80's and it would start bucking and fluctuating at around 4000 rpms. Now we have a cold streak in the low to mid 50's and it runs all the way up to 5500 rpms at full throttle. Would the outside air temp affect the fuel pressure regulator or would the mass airflow sensor or air temp sensor cause something like this?