Fuel pump / s also maybe fuel pressure regulator

Check and make sure your ECM harness plug is good and tight making good connections. Check ground on back of block.

In other words before randomly throwing money at it check the simple things first.

Question... The 4"-5" round cylinder that is approx 14" long that spands in front of the engine just under the intake, what is that? I noticed that the one side of it that feeds into the top of the block was getting very hot. Much hotter than the other side. The hoses felt fine on both sides.

I will check the grounds and re-check the electrical connection points tomorrow.

Thanks again for all the feedback.

I had crappy gas destroy the fuel filter, fuel/water separator, AND the fuel pumps on BOTH of my 496HOs, 2003 vintage, a few years ago.

After replacing all 6 components, all ran great. Then I had a drive go bad. Still missed the poker run.

The cap it off, later than night I flipped a car into the woods and put myself in ICU.
That was a pretty ****ty weekend!

I'd recommend replacing the fuel pump, and also the inline filter.

Heat exchanger.

You know this is sort of old school here but it sure sounds like a clogged fuel tank vent to me. After running about 15 minutes a partial vacumn is formed in the tank causing a lack of flow. After sitting the pressure equalizes and all is well again. See if a dirt dobber has built a nest in the vent line. You should be able to take the fuel cap off and easily blow through the vent. Alternatively you can take the cap off and run it and see if the problem persists. Don't do this if the cap is in such a position that water can enter during operation.

Good luck,

Dan

Thanks Dan,

I did try running without the gas cap on a few days ago and it still acted the same.

I've followed the fuel lines from the water seperator to the low pressure pump, then under the block amd around to the high pressure pump, then up to the fuel rail.... I don't have a fuel filter?

I'll have to remove the panel going towards the tank and see if its hiding back there somewhere.

My inline fuel filter is about 12" in front of my fuel/water separator, but that's how my boat was rigged. I'm not sure if yours is the same. But, when I did take mine off after all my stuff went south, it had so much crap in it that it rattled.

Thanks,

Is there anything inside the heat exchanger that could stop water flow or would need serviced?

Replace the crank sensor. I'm not guaranteeing it by any means, but I've seen it over and over again in the automotive world. Not that expensive and it eliminates that possibility. Just be careful not to break it off in the block.