Every time I stop the truck the engine shuts off

Hello,

I'm going to give you a possibility. Your symptoms are steering me in this direction.

Your IAC (idle air control) may be acting up.

There's a few things you might try to confirm this.

The IAC is computer controlled and controls the idle by channeling a little air over/ by the closed throttle plate in the throttle body.

The IAC is a mechanical plunger that can get dirty or worn or just flat out dis-functional.

You mentioned a rough idle, while it is doing that, give the IAC a little love tap with the rubber handle of a hammer or similar device. No need to smash it! Just a love tap!

Did the idle straighten out any? If so, we may be on the right track.

Next thing to try is to remove the IAC (yours has two bolts and a wire connection).

My first picture is what yours looks like.

Lets clean the inside of the pocket with "throttle body cleaner", carefully actuate the plunger with your finger a few times while you clean. Last, lets spray the hole the IAC covered.

Reinstall the IAC. Connect Mr. Wire to it.

Since the IAC like actuates a trillion times over the years. It is possible that it is just tired and worn out. In this case, it will be time to replace it should the cleaning may not last a long time.

That was the case with my wife's Ford Escape, it lasted maybe a month after the cleaning. The new one fixed us right up in the end.

The remaining pics are of the wife's Escape, your set up will be very similar.

Return with good news!

The Medic

Hi and thanks for using 2CarPros.

This could be a few things. First, and interestingly, the fuel pressure is a bit low according to the manufacturer's specs. Here is what they indicate:

Fuel Presure
Key on, engine off. 414-448 kPa (60-65 psi)
Engine running. 414-448 kPa (60-65 psi)

Since it is a bit low, I question if you have a couple injectors sticking. When you checked fuel pressure, did you pay attention to fuel pressure drop off? If it is dropping off fast, that could indicate an injector leak.

Let me know if you noticed that. Also, I need you to check the fuel pressure regulator. It is located downstream of the injectors. The regulator on this vehicle is vacuum operated. I have seen situations where the regulator allowed fuel to be sucked through the vacuum hose. As a result, the vehicle ran rich (which yours does), rough running and wouldn't idle.

Check that hose and see if there is evidence of fuel being drawn into it. I attached a picture of the regulator so you can see what it looks like and how it functions.

Let me know what you find. Also, keep in mind that I am assuming the vehicle is stock. If there were any alterations such as a high performance air filter, exhaust work, or anything you can think of, let me know.

Take care,
Joe