Truck lost power and died will not restart. Engine light flashed prior to this.

Have you checked the battery on it,mine did the same thing on my old chevy colorado and changed it then worked like a charm

The engine still turns without dragging, and all of the lights are working. Including the headlights. By losing power I meant it would not pull itself not lost electrical power.

see if the injectors are firing , they make a noid light for that , check for good spark with adjustable spark tester , let us know what happens

Does the 04 z71 with the flex fuel 5.3 have a fuel injector control module?

Ok I have pulled the codes, it took a while been battling the flu. P0307 and p0455. I have researched this problem some and was wondering if the crank position sensor could cause the misfire code. I know they usually throw their own code but it seems like a logical culprit for the condition I am having. Particularly since I have depressurized the fuel rails hooked a pressure Guage up turned the key to the on position and the pressure Guage reads between 55 and 60 Psi. I still have to try the noise light and the spark tester.

and what do the codes pertain to ? I sure don't know off hand . O.K ones a misfire , that could be a few things ,Spark can be checked by pulling a wire and see if there's a good arc to a ground and doing that could send up a code ,, the tester is only $8** and is more accurate you may have a weak spark , these newer vehicles are loaded with relays , modules so who knows .clear the codes and see what pops back up ..

I tested the spark it is excellent but seems intermittent. Like the timing, is fluctuating. Sometimes it will run but stutters and dies other times wonto even attempt to start. I am going to test the crank position sensor. P0307 is a miss fire on 7 cylinder. The other is the evaporated canister code.

I'm no technician , I would think a bad crank sensor would misfire other cylinders but who knows , as long as your testing it properly you'll have an answer , plug wires are ok ? I've seen a guy spray them with a water bottle to see if they arc to a ground , you're learning and it's probably not as expensive as schooling , let us know what happens .

Ok checked with a nod light and injectors are getting signal. I am thinking it has to be the crank position sensor now. I have fuel pressure I have intermittent spark and the injectors are being told to fire.

"spark is intermittent like the timing " How did you check timing ? This is starting to sound like the [nylon] timing chain has jumped a tooth ,

Just didn't seem like it was sparking like it should. When it did spark it was excellent, but it didn't fire every time the motor turned over.

Oh one more clue it did miss one time before, but it did not die. Both times it has acted up it has been pouring rain.

I replaced the crank position sensor. Still will not start. If I unplug the ecumenical to check for damage will it need to be refreshed if it is good?

Reflashed.

Ecu

I would have gone with a new ignition module but guess work is the wrong way to go ,it could be a motor/chassis ground who knows ? you probably could have taken it to a good shop and have it fixed with the time and $$ put into it , trouble is from what I read online some mechanics also do guess work and bill you anyway and you still have the problem , it doesn't sound like a computer problem that would show on the scan (right)?

Well after the advise of a friend of mine who is a tech. He says the truck has to run long enough to conduct tests on itself before it can register any codes. He said to remove the mass air flow sensor and see if it starts. Did that it still did not start. He then said spray starter fluid in the intake tube to see if it starts. Did this and after a few trys it did start and run long enough to throw a p0300, multiple misfire detected. The tech said it could be a vacume leak, plugs plug wires, many other issues and is supposed to come help me narrow it down a bit. But now I am thinking that because it has happened when it is pouring rain it may be a vacuume leak.

It's your fuel injectors. And a misfire in cylinder #7

Misfire in Cyl 7 is a misnomer. What it means is the crank position sensor detected a slowdown in RPMs corresponding to Cyl 7. There are a lot of things that can cause that, like a broken piston, bent valve, blown head gasket, etc. In my case it was a broken piston ring land.

Thank you to everyone who answered me. I ended up sending the truck to a shop in my area. They drained the fuel tank and refilled it. They said when they sent the gas off to be tested it was noting but ethanol rust and water. I did find a massive vacume leak, along the underside of the intake tube. But It has been a year and it runs good now.

I don't know why they even starting adding that crap in gas , it was a scam from the very beginning , it didn't help anyone