so i started having a p0641problem about 2 months back, it would just randomly go into limp mode while driving and then i figured out that if i have it in reverse and put foot on the brake and gas at same time it would trigger limp mode instantly no matter how long it had been running. so i started replacing parts such as, the evap purge valve, tps sensor, fuel pump, crankshaft sensor and ECM and after was still going into limp mode. so just today i replaced the oil pressure senor and camshaft sensor sense those are both on circut 1 hoping it would fix it, now it will only crank sometimes and will start sometimes but then die immediately but most the time no crank no start and sometimes i'll just hear the fuel pump priming over and over and over. and now is also throwing p0335, p0452 as well as p0641 still. this has me stumped and at a stand still, any feedback will help

 

throwing parts rarely works. Especially when a it's a system wide voltage issue that's causing all the sensors to malfunction.
How's the charging voltage?

https://www.carparts.com/blog/p0641-...-circuit-open/

 

if you are talking about the charging voltage for the battery them, when the truck is off im getting 12.6 and when it was runnung i would get a little over 13. but just checked today after the other problems have started and its at 12.6 but will slowly die the more and more i try to start it