98 12 valve. i have a in cab fuel pressure gauge. electric sender. at idel its exposed to b between 17-23 psi at 2500 rpm no load its exposed to b 25-30. im at 10-14 at idel an 20-24psi at 2500 rpm no load. when driving its usually like 10 psi if i let off the throttle an just cruise it goes to 20. then i get back into it an it will spike up to 40 then to back to 20 then up to 30 then to 10 again an stay there till i change throttle position. what im really worried about is running the truck lean.- low fuel pressure. iv changed the filter an i have a tork tek overflow valve. neither changed anything. my buddies tell me im paranoid, but i swear its not the same as it was. this truck is how i make money an my daily driver. i take very good care of it an cant afford to be broken down with a trailer in tow. im afraid my pump is going out. any help from experienced cummins mechanics would b gratefully appreciated. thank you

 

Do you have a snubber and a resistor (spelling) To check from the gauge spiking? and also do you still have the stock lift pump?

 

snubber yes resistor no. but it is fused. no relay either. its the stock pump as far as i know. truck only has 156,000. an it was babied before i got it. my mane concern is the low fuel pressure today at a stop light it was at 4 psi. but it runs super strong. towed 7k on my trailer today 70mph the whole way. then other times it feels a little dogish. im paranoid

 

You do need that resistor. So it can hold a steady pressure. But im not to familiar with the stock fp but what can help is get a hanes book for the truck and ill help you.