When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
If the anti tamper seal is still intact on the FPR then don't touch it.
If it's been removed then you'll need a WBO2 to set it correctly, clockwise for more fuel, anti-clockwise for less.
No worries. If everything is standard and the fuel pressure regulator hasn't been tampered with you probably have a duff sensor or wiring. If the ECU thinks it -20 deg C outside you will be very rich indeed.