i just put a new isspro fuel pressure gauge and a new isolator in my truck after having the last one go bad and the airdog acting up anyway when i turn the truck on the gauge will go up to about 15psi then drop down to about 4psi then as soon as i start to drive the gauge will just drop to 0 and not read anything and every once in awhile when i stop at a light it will sometimes bounce around a little but for the most part stays between 0-2psi until taking off agian when it will drop back to 0 the truck is running great and i had the airdog replace under warrenty last week and went back through and checked everything on that just in case so i'm really doubting that there is any actual fuel pressure problems and more a problem with the gauge especialy since this isn't the first on to act up on me any help fixing this gauge issue would b greatly apreciated

 

My problem is very similar, although I don't have a gauge yet I have the idiot light for the low pressure indicator. I have about 100 miles if that on the new AirDog, and yesterday i caught the LED flickering. So I nursed it home and started digging. Filters were clear, no signs of anything blocking them. So I took out the instruction book and turned up the pressure as listed in the book and went for another drive. Everything went well until I started down a steep grade and it flickered back on, and within a mile, I was shutting the truck back off because the light was staying on. I'm getting a gauge this week for use with the Quadzilla I have yet to install. Any ideas guys? I really hope it isn't the new lift pump.

 

I hate isolators and susspect some air in the line...........try it without the isolator

 

ill give it a try when i get home today thanks for the help

 

For this you will have to monitor the gauge while driving, if you want to do this, you can attach a small extension hose and temporarily attaching the gauge so it can be seen from drivers cabin. If you have any problem then replace fuel pump.

 

I put a gauge on mine and kept the light and guess what? The gauge verified what the light was saying. After about 20-30 minutes, the pressure gauge was jumping between 2 and 4 psi at idle. So again my truck is sitting