2004 Ford F-150 Idle issues

Tiny
SCOTE1
  • MEMBER
  • 2004 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 106,500 MILES
Have been having an idle issue on my 04 f150 4x4. Recently I have had the fuel filter replaced with a new fuel line as well as the MAF replaced and I would assume the shop cleaned the IAC valve at the time of the MAF. Autozones reader couldnt read my codes, so I took it to an ASE shop and they pulled codes stating the idle was surging.

This work was all done within the past couple weeks with small improvement from the fuel filter/line and a large improvement with the MAF replaced. At first I was stalling at red lights and when braking the RPMS would dip down, 70% of the time resulting in a stall - when coming to a stop. Replacing the MAF has helped remedy this issue, as now the truck idles at 500 RPM's when coming to a stop (is this a low idle in this truck? Do I need to have it raised?)

Now, the truck will stall with the wheel turned all the way to the right/left when not giving it gas. In park, the rpm's stagger, they drop around 50 and go back up to normal, constantly doing this. Especially after driving for example - an hour on the interstate.

On the interstate or going above 60+ mph, the steering wheel shakes a pretty good amount, and will return to normal in some moments. When taking off from a stop and giving the truck a good amount of gas, the truck will shake, almost sounding like the wheels are spinning. If I ease onto the gas pedal, its unnoticeable. Not really practical in all real world situations though.

Any advise will be taken into consideration, as I have just picked this truck up within the last month and need to get it on the road and 99% reliable! Thank you.
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Tuesday, May 13th, 2014 AT 6:03 AM

8 Replies

Tiny
HMAC300
  • EXPERT
Check fuel pressure with a gauge first then if still shaking move front tires to rear to see if tha tmakes a difference.
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Tuesday, May 13th, 2014 AT 7:16 AM
Tiny
WRENCHTECH
  • EXPERT
The MAF isn't going to cause an idle stall but the IAC very well could. Don't assume simply cleaning it will fix anything. Cleaning the throttle plates and throttle body would be more help can cleaning the IAC.
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Tuesday, May 13th, 2014 AT 7:18 AM
Tiny
SCOTE1
  • MEMBER
I have just gotten new tires and alignment on the truck, at the same time I got a new fuel filter/fuel line installed.

Next step will probably be to get throttle body serviced.

But would this make any shake when at highway speeds, or the shake when taking off from stops when engaging the gas pedal a fair amount from a stop?

No CEL's after MAF was replaced.

All of my gauges remain fairly steady, none of them go out of whack ever, except the RPM issue.

Thanks for quick replies!
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Tuesday, May 13th, 2014 AT 7:41 AM
Tiny
HMAC300
  • EXPERT
Normally highway speed shake if not he tires is normally ujoints in driveshaft or a wheel bearing type problem. Even if throttle body is service you shold still have fuel pressure checked with a gauge as it may be low.
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Tuesday, May 13th, 2014 AT 9:24 AM
Tiny
SCOTE1
  • MEMBER
Doesn't happen all the time, it just will randomly happen, and go away within a few moments, and MAY or MAY NOT come back later.

If indicated with a low fuel pressure, I would assume fuel pump may need replaced? I do know that previous owner was low on income and ran the truck at quarter tank for a short time.

I will have throttle body serviced and fuel pressure checked, perhaps a smoke test to rule out any vacuum leaks as well. Picked the truck up for a good price, still worth it through the small issues I have came across thus far.
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Tuesday, May 13th, 2014 AT 11:03 AM
Tiny
SCOTE1
  • MEMBER
Had the IAC valve looked at and went over. After I got it home, I wanted to test something out.

Put the truck in park, turned steering wheel all the way left and all the way right to replicate my stalling issue. Didn't happen. Tested in drive as well. Didn't stall.

So, issue now would be most noticeable after driving the vehicle. But, when shifting into drive, the rpms still drop 100-300 rpm's.

When shifting from any gear to reverse, there seems to be a "clunk". Not sure if this could be part of my issues or not.

What would I ask for to get these things looked over? There is no CEL, so I'm a bit confused as where to start.
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Wednesday, May 14th, 2014 AT 2:38 PM
Tiny
HMAC300
  • EXPERT
When you put any vehicle in gear the rpms'are going to drop. Has anything been checked that wrench tech and I have suggested if not do that first.
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Wednesday, May 14th, 2014 AT 3:15 PM
Tiny
SCOTE1
  • MEMBER
After some time of driving, the rpms in park will stagger around 50 RPM. Cutting out without giving gas on turns is still an issue as well.

I will be going to a different shop other than the recent one I have taken my truck to, hard to find a reliable shop.

Will update when I can get the truck back in.

Thanks guys.
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Wednesday, May 14th, 2014 AT 3:47 PM

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