Got a 2000 F-150 with the 4.6 and 166K miles automatic 2WD. Previously this has happened a couple times but now it has become more frequent. The trucks starts perfect every time, idles no problem, but now it has started to die when I turn a corner. If you come to a stop then turn it won't die, but if drive up to intersection and turn left or right it sometimes dies. It's like the rpms drop down to 350-400 and sometimes it jumps back up and you keep going and other times it just kills out. No check engine light comes on or anything. After it dies, you can be rolling, kick it in nuetral and it starts right back up. Anyone know what could be causing this?

 

First item I would work on it the IAC.
Remove it and spray clean with throttle body cleaner and be sure the pintle inside is free to slide.
This part controls idle.
Stuck closed the idle will be between 400 and 500 rpm.
This part keeps the idle at 650 under computer control.
No need to remove battery for this.
If you do, it reboots the whole system for relearn but will relearn over time anyway.
Good luck.

 

Hey OSU_AGR,
I've got a 2001 F150 and the exact same thing happens to me. Have you resolved your issue? if so, what did you do? I've seen other threads that say, a guy replaced his entire throttle body and that resolved the issue and another saying that he replaced the DPFE sensor and that resolved the issue.

 

I took the air cleaner and intake all off (which mine is all K&N) all the way to the throttle body. After getting it all removed, you can push the plate back that is spring loaded going into the throttle body. Mine had some buildup from the years inside there and around where that plate rotates in the body. I used some B12 Chemtool and fully cleaned the inside and outside of it especially where the throttle cable attaches to the spring, giving it a little more ease of motion. I didn't have to take the whole throttle body off but could have if I needed to. After getting it all cleaned up, reinstall the air intake and filter. When starting it up it might not run smooth right away due to the fact that it doesn't have the right fuel mixture but after a minute it clears up. I haven't had any problems yet and it hasn't died on me yet (knock on wood) so we'll see. Hope this helps.

 

Thanks a Million OSU_AGR!!! I will try that for sure and let you know. I will pick up those cleaners on Thursday and try it out and get re-post with the results!!!

and yes, the information always helps, Very Much Appreciated!!

 

Sounds good so far.
Here is what happens when your in decelleration.
The throttle is closed as you would do but the TPS tells the PCM the throttle is closed along with road speed sensing.
This closes the IAC to just the point of not allowing the motor to stall as well as shuts down fuel injection for this event.
What you hopeflly did was to 'fix' the air control the IAC is supposed to do.
The left and right turn effects are from the small extra engine loading the power steering added without proper idle control and the engine could not recover from it without air corrections.
Good luck.

 

Hey Bluegrass7 - thanks for the info,, please excuse the obvious question (i'm still new to engine repair) But how do you "fix" the air control? any information is gold!!

thanks again :-)

 

Near the top of the intake is a device with an electrical plug on it.
Don't mistake this for the TPS attached to the throttle plate shaft.
Remove the plug and the part.
Get spray can of throttle body cleaner and spray the inside of the part till it runs out clean.
Inside is a movable valve rod.
Make sure it can move freely over it's range of about 3/8 ".
Re install the unit and plug up the connector.
If you want to do the whole job, remove the throttle body intake hose exposing the throttle plate.
Check for accumulations.
Open the throttle plate by hand with the out side throttle cable and spray clean all around until it runs out clean.
Re assemble everything and let it set for awhile because starting will be rough on cleaning fluid until it all clears out.
Next remove the positive cable for about 1 minute then reconnect.
Start the motor , turn on the headlights and Fan motor to high and A/C if you have it.
Let the motor fully warm up to operating temperature.
Then go for a short trip of about 5 miles. Stop and do several hot restarts.
If all is good the cold and hot restart should be perfect and no stalling during driving.
The reason for doing this procedure is to reboot the computer, make it do all the testing and for rebuilding the idle tables to cover all the parameters it needs for idle and load control under all the various conditions.
As you drive the rest of the time, other tables are being rebuilt due to rebooting.
Good luck.
Tell us how it all works out.

 

Holly C**P Bluegrass7 this is some Great info!! I'm gonna half to print this out and tuck it away for future usage..

Thanks again. I'll do this on Thursday and post with an update.

 

Hey Bluegrass7..... so it's been a couple of days no and my truck is running great!!!! thank you for the tips here. It's even idling better now too!! The throttle body was really gunked up too, but I took a toothbrush to it and was able to get it nice and clean. Thanks again for all your advise!!!

 

HEY HEY, good to hear.
You gave me practice at diagnosing an illness like Doctor.
Put the check in the mail.
Good luck and all the best to you.