Greetings,
On my dodge, when I'd get below 1/2 tank of fuel, it would sometimes take several extra turn overs of the engine for the engine to start. Usually it starts very quickly, even in colder weather. Lately, I've noticed it is happening more often, and even at 3/4 of a tank of fuel. It seems like only sometimes I am losing my prime. The time the truck sits before starting the engine again doesn't seem to matter: Sometimes after sitting for five minutes, it takes awhile to start, yet sometimes after sitting for a few days it starts right up.

Second issue is I noticed a high pitched whistle when accelerating on the highway around 2,000 RPM. I'm guessing this is a leak in the intercooler hose, blow off valve, or intercooler? Is there a common place I should look for leaks? How can I find a leak like this? Thanks in advance for any advice!
-Lee

Regarding your first issue, I had a similar issue with my 01 and it ended up being the computer on the injection pump. I would get hard starts just every now and then, no rhyme or reason to it. When it's giving you the hard start, try cracking an injector line and see what the fuel pressure is like. Best of luck!

Could be lots of things, loosing prime is not one of them usually in only a few minutes But check all the fittings anyway including the banjo on back of the head and T fitting below it. Just look of dampness and looseness. No looseness probably all fine there. Check tank lines too.

Big check, Does the Wait to start light come on immediately with the key to ON? Warm or cold it should come on immediately every time, does not have to stay on but needs to flash on every time.

Do you have an aftermarket air cleaner on it(more turbo noise)?
Have you worked on ANYTHING lately? Start there.
For boost leaks look at all hoses and check for tight clamps. Check any bolts going into the intake plenum. When one is left out they whistle but should not affect starting.

Also just for fun check all battery terminals and inside cables for corrosion and clean all terminals to metal to metal connection. Also have the batteries load tested separately and while disconnected.

Thank you all for the replies. So I recently ran it down to 1/2 tank of fuel. It consistantly took awhile to start at this level. Once I filled the tank, it starts as it should. Do the pick up lines in the tank crack? I'm thinking this would cause my problem. "WAIT TO START" light works as it should. The batteries are fine because the engine cranks over at proper speed, plenty of power, just no fuel at first to start it.
It may have a drop in K & N filter, but not an aftermarket setup. I'll check the hoses. This whistle is a new issue. It didn't used to make that sound.

Check all the boost hoses and bolts in the intake plenum. Your noise will likely be there somewhere. But it is not likely related to starting. Are you getting fuel pressure when you do a starter "bump"? If it possible for the intake to have problem with the fuel intake, a module, line or pickup tube crack or seal. Try parking it up and down a steel slope with about a half a tank to see if there is any difference. Don't for get to check ALL the banjo joints on both intake and return system. Just put a wrench on them and check them for tight but don't strip. Fluid leaks are not usually visible. Also check the fuel heater plug bushing in the fuel filter top housing for leaking when running. This is a common and visible leak on the intake side.

Someone found a leak on the intake plate that made a whistling noise. Just tightening the bolts cleared it up.