So i have a 2000 Dodge Ram 2500 and I just put an FRRP Raptor 100gph pump on the truck. before the truck wouldnt go above 4 psi even when i bumped the starter. now it jumps up to 21psi when i bump it but then when i start it and wait about 10-15 seconds FP starts dropping and doesnt pick back up... any ideas?

 

Does it ever come back up after driving? Mine will drop about 4psi when the grid heaters cycle, but will come back up after they stop

 

no. i dont chance driving the truck because the LP drops below 4 psi of fp.