Two months ago my dodge started having trouble starting. I replace fuel filter immediately. Ran great for about 1-2 weeks. Started to have problems again replaced fuel filter started great. In the past 2 months I have used 5 fuel filters thinking there might be contamination in fuel. Have taken sample from canister see nothing to the naked eye. Replaced fuel pump in take still having same problems. I don't believe it is fuel injectors due to when running after started runs great gas mileage 16-18 mpg. I'm thinking it has to be something between fuel tank and fuel filter due to when I change filter it starts right away. Anyone with suggestions

 

On the fuel rail there is a pressure relief valve. Remove the return line from the top of this valve and while someone tries to start the truck, see if any fuel is leaking out. If there is, then it could mean that the injectors are not receiving the required fuel pressure and/or quantity to start.

 

I agree with Mexstan (like I know what Im talking about). Also, when I finally get around to it, I am going to install a fuel pressure guage on mine. From talking with the guys here, FP is the root of a lot of problems.

 

I don't know if the 03's are the same as the 98's, but ours was experiencing the same problems. It turned out the problem was the steel lines that come off the top of the tank had rusted and had a hole in them right where they make a 90 degree bend. It would allow the fuel to drain back to the tank after it was shut off but ran fine once it was started. Had to replace the whole assembly that goes down into the tank but it solved the problem.

 

had similar issue with my 03, finally got to the point it would only start if I pulled the fuel filter out completely. I know, sounds stupid but when your broke down it dont matter. Do a search on here for pressure relief valve, I wound up putting a bolt in the hole, fixed the hard start problem until I finally sold the truck 6 months later.

 

ok sorry it was the fuel limiting valve that was my problem, dealer wanted 2,000 to replace the lift pump and FLV. Here is a copy of the post that fixed it First off if that's your problem don't pay that. Here's what you do the limiting valve is what we call the rail relief valve. The location of this is to the right off the rail sensor and is mounted on the rail. Take the banjo bolt out, carefully bend your fuel return line away just enough to loosen the valve make sure as you are lifting the valve out you pull it straight up out. Now as you are pulling it out and if the fuel starts dipping out the bottom then that valve is bad so go to a hardware store (take your banjo bolt w you) and get a 14mm x 150 thread pitch and cut it down to the banjo bolt length and cap your rail off so you will not have to buy that $400 switch then go buy a Fass of Glacier fuel kit for less than $700 and you are fixed.:

 

I had this EXACT same issue with my 03. This problem haunted me from about September of '10 until June of '11.
Mine began cranking for a long time before finally firing. One day I went out and it just did not start at all. I changed the fuel filter and bang it fired right up and did so for about a month. Then same thing no start out of no where. And like your situation when it did start up it ran fine and you would not know anything was wrong. Long story short, did the whole pressure relief valve thing, changed my lift pump to a raptor100, changed my cp3 pump, flashed the ecu. Finally after going to 3 diesel mechanics and a dealer I took it to a performance diesel shop and they pulled the injectors and sent them off to be tested. The test came back that i had a bad injector. They changed it and has started like new ever since.