2006 4.6l / Stalls at stop signs, red lights, and slow turns. My truck has been doing this for 3 years. Throws a code for crank position sensor, also will say unexpected low idle which would explain why so many of us have low oil pressure while this is happening. So after years of worrying and reading these forums and stalling at stop signs I take to the shop. And it was the throttle body needed cleaned. No more problems. Runs like a new one. I have used Lucas fuel treatment for years in this truck. Im a big fan of their products. When this problem began I was adding Lucas with every tank of fuel. I buy it by the gallon jug. I used some Lucas from this same jug on the wifeys Denali and her truck stalled out once or twice. She wouldn't ever let me add any to her gas again lol, I argued with her that it wasn't because of the Lucas additive. Never the less it never stalled again. Maybe I got a bad batch, maybe I used too much, or maybe it had nothing to do with the additive. But I thought it needed to be mentioned since it is supposed to be a cleaner, and since I carried it in my tool box and added it to almost every tank of fuel. I was adding about 7 ounces per tank. Who knows? But the problem with this truck is that the throttle body did need cleaned.

 

Our F150s have electronic throttle bodies that control all air flow. They do not use IAC valves, or TPS. It is not a serviceable part, however they can be cleaned and do need to be clean at least every 100k miles. The oil and crud being recirculated into the engine via the PCV valve tends to gum up the underside of the throttle plate and the lower section of the throttle body bore. This can lead to all types of different problems, from stalling to forced ide condition (i.e. no throttle response). To clean them is easy, just make sure to just a carb cleaner that is electronic throttle body same, i.e. junk, seafoam deep creep, etc. Disconnect battery, and remove air cleaner from top of throttle body, then remove 4 bottles from throttle body to intake. There are a couple of electronic connections which are easiest to remove once the the throttle body is loose. Make sure to place a cloth or towel over intake so that nothing falls in while the TB is off. Take care not to force the butterfly open and closed as this can damage the servo and sensors. You can move it gently and slowly. Reinstall, start and let truck idle for 5 minutes to re-establish TB settings.

 

Awesome write up man, I appreciate it. I guess that's what my mechanic did today because he said he cleaned the throttle body and it only took him a little over an hour. Its running great now. One thing I would like to ask you since you mentioned the pvc valve. Is this supposed to work like a one way check valve? If so then mine is shot and that may be why my throttle body was so bad. I took mine out and could blow through it in either direction like a whistle

 

If you have the PCV valve it should rattle when shaken, and no you should only be able to blow thru it in on direction. You can clean them with carb cleaner, but it should be cheap enough to just replace it.