Hello I have a '99 E-150 work van with the 4.6 engine. has around 140,000 miles. a couple of times now it has died out after starting even before I can put it in gear. The engine will rev if I give it gas but will die out if I let go of the gas pedal. I have found that if I unhook the battery for a couple minutes it will restart and run fine.
Has never died out while running and no warning lights come on. This happens probably once every couple months. Any help is appreciated.

 

Clean the "Idle Air Control", IAC motor, plunger and throttle body passageways with carb' cleaner.

Make sure there are no vacuum leaks...anywhere.

Clean MAF sensor.

Remove and clean EGR valve, and related passageways, and make sure it's not stuck open, and that no vacuum is going to valve at idle.

How long since a tune up? Plugs etc...? Fuel filter change? Air filter?

 

thanks for your reply. I failed to mention that when it dies out, it does not sputter (like a fuel problem). seems like electrical. plugs, wires, filters all under a year old

 

Then what comes to mind first is the IAC motor, and then the MAF sensor. Followed closely by the EGR system.

Note: ..."engine will run if I rev it".

 

thanks thexlo8ers for the info. I'll give it a try

 

Note too: Inspect the inside of the clean air tube at the PCV hose connection for moisture, oil and sludge. If evidence of PCV backflow is found replace the PCV system with revised PCV kit: YL3Z-6A603-AA.

This hose is in direct line with the PCV valve to the IAC motor. It will cause the IAC to malfunction if it is dirty. Check too the hose(s) are not collapsing from deterioration.

This is also important to note when the complant is; "I cleaned the IAC and it ran good for a little while then started acting up again. Then I changed the IAC with a new one and it ran good for awhile then".....

http://www.f150online.com/galleries/...940-182951.jpg

Photo of PCV hose. This may be similar to your van.

 

idle air control sensor is sticking, the throttle body needs to be cleaned out inside or the throttle position sensor ! how old is the fuel filter ? it might be starting to get pretty dirty !

 

before I start work on it, was wondering why unhooking the battery seems to fix the problem?

 

Before I attempt to answer this question it is important to acknowledge the limits of gainning information to fix problems using forums such as this.

From where I stand the best I can do is give hints as to possible solutions. However, it is next to impossible to make a pin point diagnosis. The sample of data is too small. It is akin to drawing a glass of water from a lake, and if there are no fish in the glass, pronouncing there are no fish in the lake.

That said, when you disconnect the battery "adaptive logic" memory is erased, and the system(s) defaults to a "happy" medium that controls output devices.

Then, as the vehicle is driven, adaptive logic changes, and if the output device is too far out of spec' the changes make the vehicle run worse.

The IAC motor for example is an output device. (Not a sensor.) Too far out of spec' due to contamination and/or defect the ability for the adaptive logic to compenstate for normal "wear" is compromised.

Inotherwords, as signals change from the PCM (Powertrain Control Module) to the an output device, other factors that are not present at default mode begin to become into effect.

Look forward to other posts from you.

 

sometimes unhooking the battery resets the idle air control sensor !