Anyone know where I can find what the correct fuel pressure should be on my 2004 Silverado 4.8 Liter VIN V?

I am trying to troubleshoot P0300 random misfire so am going through potential causes one at a time. The engine starts and seems to run fine but whenever I get out on the highway, the "check engine" light comes on and sometimes begins flashing. I checked the fuel pressure at ignition "on" with engine not running and get a 50 PSI reading. So if this number is borderline low, I'm thinking this COULD be a cause for random misfire. So I would like to know what the official fuel pressure number (or range) is from GM.

 

between 50 and 60

 

Do you know what the official GM number is? and the tolerance +/- ?

 

i want to say they specify 52-60, i know on my 02 4.8 it was down to 23 and running. didnt miss but idle sucked when cold and wanted to stall and if you tried to pass someone it had no power