02 ram 3500 5.9 Cummins. When I remove the fuel cap the tank releases pressure, is this normal? I looked for a breather for the tank but didn't find one. What I did find on the fuel module was a suction, return and capped 5/16 port. I removed the cap and attached a hose to it then blew into the tank. I could hear bubbling so I figure this is a auxiliary suction port? Dose this tank have a vent? If so where is it located. The reason for these questions is I feel it has a starting issue. In the morning, cold start, WTS, crank crank crank, short start and dies. Ignition off, back on, WTS, crank crank crank, starts and runs fine. This is 90% of the time. When warm crank crank start, always. The other 10% of the time it's ignition on, WTS, crank crank crank, crank crank crank, crank crank crank, start and runs fine. I have a new afe filter being shipped to me it is questionable. Lastly the fuel pressure gauge should be here next week, isspro AV-2. The electric fuel pump is on a manual switch. I turn it on and off. It is located forward of the tank. 

Update, just test drove the new RV 275 injectors and connector tubes. No more high pitch tick tick tick, no more pressure in my fuel tank and no more slobbering fuel on #6 injector tube where it connects to the high pressure line... Now to figure out where the coolant leak is... I cleaned up the engine and will fire it up in the morning, checking for the coolant leak at the rear of the head.... Thanks again for all your help.....

Actually be best to get a coolant system pressure tester. Pump the coolant system up while the engine is cold. Now leave it sit for a half an hour. Now you should have a nice trail leading back to the leak.  A hot engine might evaporate the coolant before it hit the ground like my 1996 Dodge did. It was losing coolant out of the front of the manifold but drying up before it dripped on the ground. When I pumped it up and left it I had a nice little puddle and follwed the wet track to the source and knew exactly what to do... Change the manifold gasket. 

 

I will rent one from the parts store in the morning and give it a try....