2001 Screw 4.6L


It has happened a couple times now. Twice last year within a half mile of each other. I was headed down the interstate, the truck died as I was stopping for a light right after getting off the interstate. 1/4 mile later it cut off again at the next light. Neither time did I feel the truck cut off, the steering wheel was suddenly hard to turn.

Today I was making a hard left turn. I was on the brakes hard, turning left when the wheel was suddenly hard to turn. Luckily it didn't lock. I was able to stop, put it in park, and restart it before getting run into. What can cause this? There was NO indication that it was going to cut off and at no time did I ever feel the truck cut off. From other forums I've read that it could be IAC, TPS, or bad ground. Prior to each time it cut off it was running like a top.

As you can imagine, this issue could lead to a bad situation if it continues to occur. Any ideas?

 

Iac.

 

Ports, IAC itelf, or "yes" to both?

 

Usually you get 3 posts to convey 1 message, this time it is one word for some reason....

The last time(s) my 5.4L 2001 stalled in those conditions it was a dirty IAC piston.

If you remove the IAC and clean the inside of the piston it should stop.
- Could be an actual problem with the IAC, but best to start with a quick cleaning.

I cleaned mine 2 times and then replaced it just as a maint cycle item. Dad still has not had a problem with it stalling ( he has it now for a work truck ).

Here is the piston inside the IAC that gets gummed up.

 

Iac itself, - they can get carboned up with time, -makes them sticky.

 

...or

Were you low on gas? My 01 Expy and the other 01 Expy that I sold BOTH used to stall coming to a stop or in turns when I was low on fuel. I have not had that happen on my F150, but sometimes the tank gets bent and you're lower on fuel than you think, or maybe the sump in the Expedition is poorly designed. Just some fuel for thought.

 

Thanks for the replies. Kinda figured as much on the IAC, but had to ask. I haven't cleaned the ports or had the IAC off in a couple years and 10,000's of miles. I have an ultrasonic cleaner that I might try using to run the IAC through. I have a "spare" one somewhere in the garage. If all else fails I have $60 in store credit/cards for VatoZone. FWIW I was NOT low on gas, above half a tank each time.

 

All you need to clean the IAC is WD-40 or Deep Creep and a screwdriver to work the piston against spring pressure.

 

I'd just replace it. I have an Autozone one in my truck been there for 5 year no issues it was 40 bucks but you can get the motor craft part at rock auto for 62+shipping

 

This may sound stupid but I had very similar problems with my 89 Mustang. It would shut off going around a right hand turn and coming to a stop. I could not for the life of me figure out what was wrong? It took me a solid month working on it everyday to figure out that the baffles inside the gas tank broke loose. Never seen that happen before until it happened to me. Not even sure how it happened. Just some food for thought? Im unclear how the tanks in the F150s are internally designed compaired to the mustangs.. Just wanted to throw that out there.