# Trouble with a 2007 F150 5.4 Triton motor



## wiley199 (May 22, 2004)

My sons 2007 F150 has problems. First the cataletic convertor was stopped up so we replaced it, now it starts great, idles good, but when you give it gas and it idles down it starts dieseling and dies. Changed the fuel filter, cam sensors, removed the fuel tank and cleaned it, which was dirty, filter was also dirty. This truck is in the shop and the tab is running so I need help. THANKS IN ADVANCE FOR ANY INFO.


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## wakeupluis (Feb 16, 2006)

any check engine codes? It would not suprise me if it spit out a spark plug. I would check all the plugs make sure there is no black exhaust soot all over them.


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## goodwood (Mar 30, 2009)

How many miles? Sparkplugs are definietly an issue. They break off during removal.

Looks like you handled most of the common problems with that motor. Also check the COPs- coil over plugs.


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## Sugar Land YAK (Jun 19, 2004)

*Be Sure to Read this!!*

http://2coolfishing.com/ttmbforum/showthread.php?t=459665


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## wiley199 (May 22, 2004)

Plugs were changed, I checked for a IAC and was told the 2007 does not have one. Does the 2007 have a IAC ? That stands for Idle Air Control


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## Bayman (Oct 18, 2004)

Could be the coils. It could also be the cats. There are two cats on the 5.4 with O2 sensors on either side of them. I believe one of the O2 sensors is actually mounted in the cats. I had trouble with mine after I had the cats changed. Ended up having to change a few sensors too.


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## Gottagofishin (Dec 17, 2005)

I was going to suggest O2 sensors or MAF. My guess would be O2 sensors since you just replaced the cats.


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## 300 win mag (Nov 19, 2012)

check fuel pressure?
Clean MAF maybe?


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## sam7 (May 25, 2010)

07 f150 doesn't use an idle air control valve, it has an electronic throttle body. it will usually have a check engine light or wrench light. since plugs have been changed, i'd have fuel pressure and fuel quality checked. i agree with racer x, it doesn't hurt to clean the mass air flow sensor. check under the air filter to make sure there's no restrictions


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## j-haynie (Sep 5, 2008)

If you got aftermarket plugs I would pull and check em. They are bad about the porcelain cracking when installing ang giving problems like that. I would buy plugs from a dealer and retest. Let us know what fixes it


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## LPTXGUY03 (Jun 8, 2011)

*Truck*

Sounds like a dirty throttle body or a bad throttle position sensor.


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## loco4fishn (May 17, 2010)

Tell the mechanic to keep it and get a Chevy!!! Sorry I couldn't help myself.


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## oOslikOo (Jul 13, 2010)

fuel pump?


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## jamesvaughan (Apr 29, 2012)

all the plugs/fuel injectors/wouldnt go out all at the same time . put a pressure gauge on the fuel rail there is a schader valve just for this and watch the pressure . i would also watch the voltage to the ignition


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## Ah Yeah (Apr 14, 2009)

i agree with JV. its not above the cats to be blocked off again, choking the motor out. get rid of them, put some MIL (missfire intermitent light) eliminators plugs in and be done. yes it will still pass emissions.
i have also heard horror stories about the ECM over fueling the cylinders, causing hydro lock or sending a piston into the oil pan. possibly check the oil to see if there is a gas smell to it. just my 2 cents.


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