Running rough when started
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Running rough when started
I have a 2000 F150 5.4 with about 120,000 miles on it. I changed plugs about 20,000 mile ago and the truck has always ran great but now sometimes when I first start it hot or cold it will run rough spitting and sputtering when you press on the gas it smooths out and as soon you start driving it runs great after that. Could this be clogged fuel injectors. I replace the fuel filter the same time I did the plugs.
vanman250
vanman250
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From: Over Yonder, MN
I had that happen once a long time ago, turned out to be the fuel pump. But I'd start with the IAC, it could sticking a little bit. The pressure regulator is another place, but I haven’t seen too many of those go out on fords.
Last edited by screwy; Sep 2, 2007 at 10:12 AM.
Cargo Master
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From: Central NY
Idle Air Control valve I believe...there are many posts on it, including pics.
involves 2 bolts, removing, cleaning and reinstalling. it's right behind your "cover" that says "5.4L" on top of the engine.
involves 2 bolts, removing, cleaning and reinstalling. it's right behind your "cover" that says "5.4L" on top of the engine.
Cargo Master
Joined: Dec 2006
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From: Central NY
Originally Posted by vanman250
What is an IAC?
vanman250
vanman250
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I read through the IAC post and it doesn't sound the same as mine. Sometimes when I start it it runs rough and sometimes it runs great but when it I start it and it has a rough idle if I hit the gas a bit the problem goes away and doesn't came back sometimes for weeks. I guess it would hurt to clean The IAC.
vanman250
vanman250
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Also sounds like a Fritzing TPS symptom. The TPS signal is perhaps the most critical, major control for FI & ignition.
Is that 120K on the original TPS? Its just a little, el cheapo, rheostat that gets flicked from 0 every time you "hit the gas". (Ever have an stereo that made hashy sounds when you turned up the volume?) Had 1 that struggled at idle speeds, but cleared at higher speed where the carbon resistor wasn't so toasted. Replaced it & years later developed, maddeningly elusive, intermittent, serious missing at any speed. After a miserable series of detours replacing more likely candidates, to no effect, I bought a fault code reader. Jumping out & plugging it in, when the intermittent missing occurred, finally revealed the unexpected, a TPS code. This time destructive analysis revealed that 1 of the tiny internal connections between the leads & the lousy little rheostat was Fritzing in any position. Another TPS quickly nixed the gremlin.
Originally Posted by vanman250
it has a rough idle if I hit the gas a bit the problem goes away and doesn't came back sometimes for weeks
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