I have a 2007 Volvo XC90 V8 AWD. The dealership told me that the check engine light came on intermittently and the reason was the fuel pressure sensor is faulty. It costs $525 to replace it. Is this the right price? If I delay the replacement for a while, what would be the consequences?
We don't do price/shopping questions here. To get an idea if $525 is a reasonable cost for replacement, ask another mechanic or another dealer in your area.
Did you see the "check engine" light illuminated, or has it merely been reported by the dealer? Erratic or incorrect fuel pressure would certainly trigger the "check engine" light, and may generate poor engine running or no running at all.
If you delay the replacement, the car may run poorly or the engine may stop running. It's unlikely, however, to be further damaged. It certainly will not pass an MOT or DMV or emissions review if they're called for in your state or country by the re-registration or sale of the car.