Hey Everyone,
I too just purchased a 2001 F150 XLT 4x4 and it also has had a rough idle since I drove it off the lot about 3 weeks ago.
The problem is not apparent during warm-up but as the 5.4 engine get closer to operating temperature the rough idle gets worse. This rough idle is in drive with the brake on, such as setting at stop light, and give you the feeling you have a nervous shake though out your body. My wife can even feel it in the Passenger seat.
I took the truck to the dealer with about 400 miles on it. They did comfirm my concern but did not have a explanation and wrote it off as winter blend fuels. They said they contacted Ford for issue about rough idle but found nothing and said Ford suggested I run about 5000 miles on the truck and if the trouble still exists to bring it back.
The engine will smooth out some if I hold the accelerator down to about 700 rpms but that is hard to do, because the engine seems to surge a bit at that level. The sticker under the hood says the idle cannot be adjusted but was wondering if any has tried that.
Any, just want vent my frustrations as well. If anyone comes up with a solution please let me know.
Thanks.

 

My new 01 HD is so smooth at idle or any speed I as impressed. I've never driven a vehicle with an engine this smooth. I only have 700 miles on it but sounds like something is up with yours. Winter blend fuels in TX?? I think I'd push the issue a little. They figure you'll just get used to it in 5k miles and not come back.

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- 2001 F150 Harley Davidson Special
- 1993 Mazda Miata, wifes car
- 1994 Harley Davidson Heritage
- 1976 Honda CB750K, Original
- 1965 Honda 305 Dream, Original
- 1971 Triumph Trophy 650, Original
- 1971 Norton Commando
- 1970 Honda Trail 90, Original
- Yamaha 500 Short Tracker, racing #69
- 1984 Yamaha Virago 1000, wifes bike
- 1981 Honda Passport 70, wifes bike

 

When computer controlled engines are first started (cold) the computer controls the engine based on a preset program rather than on readings from the various engine sensors. This is known as open loop mode. Within a few minutes, as soon as the O2 sensors heat up, the computer switches to actually reading all the various sensors and making adjustments based on these sensor data. This is known as closed loop mode. That's why O2 sensors have electric heater elements in them - to get them up to operating temperature quickly to minimize uncontrolled open loop run time.

Obviously your engine runs smooth during the open loop period and then gets rough when the computer switches to closed loop. My guess, you have a bad sensor that is causing the computer to mis-adjust mixture or timing. The big question of course is which sensor, and that's what warranties are for.

Tell your dealer to troubleshoot and fix your truck! It should not idle rough. My '99 5.4 doesn't and neither should yours.

 

mmgrafx,

I agree with Hawkeye...My 2000 F150 w/5.4 runs smooth as the day I drove it off the lot with 19 miles on it. I now have almost 10,000 miles on her and still running smooth. Last winter I took her up north to visit family and the winter blends there did not affect the idle one bit. Ask for the service manager and demand satisfaction. Also, do a search here on the site, several other folks have had a simular problem of this nature. That well you will be a bit more prepared. These are great trucks, don't let a lazy service tech get the best of you. Good luck!!

 

mmgrafx,

Check the oil level in your tranny. it must be at operating temp and on a flat surface.

Regards

Jean Marc Chartier

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00 F-150 XLT SC Flairside 4x4 4.6 w/5spd 3.55LSD
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Custom air intake system with modified
air box, Ported Throttle body,
Shortened MAF sensor tower,
K&N air filter,
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like hawkeye was saying, it sounds like a computer/controller issue... if it runs fine when its cold then its probably not an engine problem because that would be the time when it would run worse if the engine was messed up... when you turn the a/c on does the idle improve... i had a honda that used to idle at like 550 with no accessories running, and it felt pretty rough at that rpm. when you mashed on the brake or turnd on the a/c it would speed up to 800 rpm, which seems more reasonable for such a small (1.5L) engine.... i never had a problem with it in 90,000 miles though... just annoy the dealer long enough, they'll fix it eventually.

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2001 F-150 XL SWB
4.2L 5-spd, 3.55

 

MMGRAFX,
SORRY TO SEE YET ANOTHER PERSON HAVING THE ROUGH IDLE PROBLEM THAT MANY OF US HAVE. SOME TRUCKS HAVE IT AND MOST DON'T. I'VE BEEN FIGHTING THE PROBLEM SINCE AROUND 4500 MILES ON MY TRUCK. IT'S BEEN IN THE SHOP OFFICIALLY 5 OR 6 TIMES AND UNOFFICIALLY ABOUT 25. STILL NO FIX. CHECK OUT MY THREAD AND TRY SOME OF THE POSSIBLE FIXES THAT OTHER PEOPLE HAVE LISTED. SOME HELPED AND SOME DIDN'T. GOOD LUCK AND KEEP US ALL INFORMED ON YOUR STATUS. WERE ALL ONE BIG FAMILY HERE TRYING TO GET OUR TRUCK
RUNNING LIKE THEY SHOULD.
https://www.f150online.com/f150board...ML/002167.html

 

mmgrafx and anyone else with this problem. Read 36racin thread on rough idle. This tells the tale of many rough idle owners. For 2 years I listened to ford tell me this was a normal characteristic. Myself and MikeinLA would not take this as normal and filed a case with the Dispute Settlement Board. They in turn ruled that our truck did have a more then normal rough idle and awarded us a new truck or a 100% buy back. Trust me you will get bull sh#*ted around as long as you deal with ford and your dealership.Read your owners manual and read up on the procedures for filing a case with the DSB. Also read the post rough idle, It may take you a day to read all the messages but it will save you a lot of aggrivation on trying to get this problem resolved.
ford cannot and will not fix this problem