2003 Ford F-150 service engine light on & occasional rou

Tiny
DEEREY
  • MEMBER
  • 2003 FORD F-150
  • V8
  • 2WD
  • AUTOMATIC
  • 113,000 MILES
Hi
The Sevice Engine Soon light came on a few days ago and on a couple occasions the enigne started idling rough (this happened both times, oddly enough at the drive-through window at fast food restaurants, could this be a hint of some type!) I put the vehicle in park and gave it a little gas and it seemed to clear it up. Vehicle runs fine otherwise.
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Saturday, April 24th, 2010 AT 6:40 PM

9 Replies

Tiny
MHPAUTOS
  • EXPERT
Hi there,

Thank you for the donation,

Hmmm fast food and rough idle. Maybe your car is telling you something. Lol. Seriously this could be a problem with the idle control system, but with the check light on, you will have a set fault code in the ECU, a scan will read this code and this will help with the diagnostics, get a scan done and report the code here for more assistance.

Mark (mhpautos)
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Saturday, April 24th, 2010 AT 8:57 PM
Tiny
DEEREY
  • MEMBER
HI
Thanks for your quick response.
To add to the problems I'm already having the truck is now stalling out while idling in gear plus it appears to have a slight hesitation when revved up. I stopped by Autozone after I got off work today and an associate plugged in one of those analyzers. I don't remember the code it came up with but he said the code meant that the air/fuel system could be dirty & sold me some Sea Foam fuel treatment to put in the gas tank. He said it may take up to 200 miles of driving for the problem to clear up. Unless you all have any other suggestions I guess I'll play wait & see for now. Thanks
Doug
P.S. If this is any help the vehicle appears to run worse after it has warmed up.
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Sunday, April 25th, 2010 AT 6:52 PM
Tiny
MHPAUTOS
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Hi there,

The actual code will be a big help, but in the interim, see how you go with the cleaning agent, let me know how you get on.

Mark (mhpautos)
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Monday, April 26th, 2010 AT 1:44 AM
Tiny
DEEREY
  • MEMBER
An update to a prevous reply. I tried the fuel treatment Autozone recommended but it didn't do any good. I went to Adavance Auto Parts yesterday, they ran a check and came to the conclusion it could be any one of the four Oxygen Sensors may be bad but wasn't able to tell which one. He recommended taking it to a shop to have it further tested. BTW the codes coming up are as follows: PO 171 & PO 174. I think he said it said with the codes "System Lean Inboard" & "System Lean Outboard" if that is any help. Thanks
Doug
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Saturday, May 1st, 2010 AT 1:11 PM
Tiny
MHPAUTOS
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Have you checked for any vacuum leaks as yet?

Mark (mhpautos)
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Monday, May 3rd, 2010 AT 6:47 AM
Tiny
DEEREY
  • MEMBER
Hi Mark
Yeah I've done a check on that. I have one vaccuum line in question that runs back behind the throttle/choke area that seems to have some dry rot (it seems like the line has some type of "skin" to it that is peeling off and cracking when disturbed). I unplugged it and the vehicle's idle dropped significantly more when I did that, short of stalling completely. It appears to be like a "ready fit" vaccuum line for it twists and turns like has been made to do so. Any input on this would be gladly appreciated.
Doug
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Monday, May 3rd, 2010 AT 6:58 PM
Tiny
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If any rubber vacuum lines look at all suspect they should be replaced, inn most cases the rubber hose can easily be replaced, as long as there is no sharp bends or kinks in the line there will not be a problem, so if this hose looks suspect look at the end and see if its just a small section off rubber hose fitted over a steel pipe.

Mark
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Monday, May 3rd, 2010 AT 7:55 PM
Tiny
DEEREY
  • MEMBER
UPDATE: I changed that vaccuum line out that looked bad but it didn't help. I took it to the dealership (the only place that would look at it today). They replaced a rather large vaccuum hose that went from the valve cover on to the very top back of the engine (the hose was rotted out on the back part - it was so far back in there I never saw it). Even though I shelled out nearly $200 for the repair (it's a dealership) at least it's back to running proper. Just the same thank you all for your help in this matter.
Doug
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Wednesday, May 5th, 2010 AT 7:34 PM
Tiny
MHPAUTOS
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OK thats good that you are back on the road, the problem is that there are so many vacuum hoses on modern engines, you do have to look all over as it could be any number of them causing you a problem,

Mark
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Wednesday, May 5th, 2010 AT 8:05 PM

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