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I've experienced this problem the last 3 times I fuel the truck. It turns over but fails to start. I tried disconnecting the battery and re-seating the fuel pump relay. Neither seemed to have any impact. Eventually, it started after several attempts ranging from 15 minutes to 40 minutes. Once started and running I have no issues with fuel delivery or starting until the next refueling.

The immobilizer was initially a suspect but the last incident I observed the flashing light extinguished once the key was inserted. I did try a spare key to be sure.

I am aware of numerous fuel pump issues with these trucks. There is a TSB relating to failed fuel pumps but getting a dealership to repair under extended warranty is often a challenge.

Has anyone experienced this and was there a resolution?
 

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I found this post I copied and pasted from another forum. "
I have 5.7L, non flex fuel, well maintained and usually runs fine. Once every while (and randomly) the truck will crank, crank, crank, and not fire. Sometimes it is after sitting overnight, sometimes after just running inside the store real fast. Like I said, random. (I am cranking to start it without touching gas pedal...I will get to the relevance later.)
No code, No check engine light. Good gas, and gas treatment. Cleaned and inspected intake and throttle body.

1. The next time it happens, I spray a bit of starter fluid in the throttle body, and it sputters and want's to start, and eventually it does. So what we have is a fuel delivery issue, not spark. Fuel delivery is very much dependent upon no vacuum leaks and measuring the air intake. Checked all vacuum leaks, found none. I suspected a bad Air Flow Meter (AFM) located between filter housing and throttle body, but at $150+, I didn't want to just start throwing parts at it. (Basic function of the AFM is to measure how much air is going by it and "tell" the computer to adjust fuel ratio, among a lot of other things.) Also, since there are no error codes or check engine light, I don't think it is the AFM. Error codes are only thrown by problems that the computer can detect through a variety of sensors (included the AFM). So, if you have a problem with no error codes, it is likely "purely mechanical" and not being picked up by any computer sensor. Examples would include bad gas, dirty filter, bad vacuum lines. (Although, some "purely mechanical" issues may eventually lead to issues that do throw a code if not fixed.)

2. I suspected maybe a bad Fuel Pressure Regulator. This vacuum controlled device is on the fuel rail on the RH (passenger) side of the engine. It has a vacuum line going up near the throttle body. This basic device uses engine vacuum to move a diaphram that allows more or less fuel into the fuel rail (which wraps around to all the injectors). The more vacuum, the more fuel. It is purely mechanical, not a sensor, and no wires go to it. All kinds of symptoms happens if it is bad. I've ordered one, but doesn't come in until next week.

3. The more I thought about it, I kept coming back to thinking it is a vacuum issue. So, the next time it would not start (just crank) I tried something -- I pushed the accelerator pedal to the floor and THEN cranked it. A couple of cranks and "vrooom" we have liftoff. The next few times I had the issue, this solution worked to get it started. Hold the gas pedal to the floor, crank, and it starts. After that, ran normally. So, what is up with that? Well, by holding the throttle body open while you crank you are allowing the engine to "suck" in more are....so more vacuum is created than just turning the key. (Also, more air flow past AFM and more vacuum to pressure regulator=more fuel.)

Obviously, the truck is designed to provide sufficient vacuum and air flow at startup without this "trick", so something is up. Now we just have to figure it out."
I intend to try this the next time the problem presents itself.
 

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Incorrect theory ...With throttle plate OPEN while starting or at low rpm you have almost no vacuum . Zip.
True with throttle plate open while cranking you have more air going threw the intake . ill buy that .

Do not confuse more airflow means more vacuum
 
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