I am at a bit of a loss now. From my sig, you see I have a Dipricol FP guage. it is hooked in with the isolator and up until a month or so ago was working fine. My readings were all what I would consider normal. One week, I ran my tank down pretty empty. Sometime after filling up, I noticed that my FP gauge was not reading barely 5 pounds of pressure, constantly. No load, under load, cruise. Odd. Kind of let it go for a bit and watched it. Most times it was around 5 pounds. Then, one cold morning, I fired up and the needle didn't move. Now, my gauge is hooked in at the IP Schrader valve. Drove to the coffee shop. When I restarted, it went back to somewhere under 5 again. That circumstance happened once more and I decided to have the FP checked. On the inlet side of the filter, I was getting 14 pounds. Ah HA! Plugged filter. No surprise. Replaced the filter, bled the system (including the gauge at the isolator). Power seemed to come back (at least I thought it did) and my pressure went up to 8 or 9 pounds. But that didn't last long. I am now right back where I was. Another filter plugged??? I put in a NAPA fuel filter. Ideas?

 

Check your FP with a hand held gauge at the VP schrader (since this is where your in-cab gauge is hooked up) - not pre filter.....this will verify if there is a problem with the gauge or not.

 

That's the only think I haven't done yet but was kind of assuming a functioning FP gague. It's a pretty simple affair.