2004 f150 4.6lt Triton

Asked by Jul 20, 2017 at 11:38 AM about the 2004 Ford F-150 XLT Ext. Cab

Question type: Maintenance & Repair

My truck was running fine. Then coil pack
went out.. i have replaced all of them. Put
new plugs in. New fuel filter. Complete oil
change. Fitee breather filter everything. Even
a fuel rail cleaning. Still when its cold it runs
great. But after running for a while truck
shakes really bad. At idle shakes really bad.
Wont accelerate quickly power of motor real
low. Between 1500 &200 rpm bad shakes.
Over 200 rpm shaking stops but truck has
no power.. when warmed up sounds like a
diesel. Spent a grand now. Just got a new
brain box but still cant read codes. Please
help.

2 Answers

25

Sounds like your cylinders are misfiring. Make sure that the plugs you installed are to spec, meaning make sure they were gapped correctly before installation and that the plugs were made for that particular engine. If coil packs were replaced, those should be fine.. You claim to have cleaned the fuel rails but you could have a failing fuel injector. For starters, I'd get the OBD-II working to check out the codes and then just google for code interpretations. Hope this helps.

20,440

Since you spent all the cash I suggest you spend another hundred bucks and have a mechanic do a live data analysis on the engine while it is idling. It does sound like a misfire in one or more cylinders, but what is causing the misfire is the key. It could be bad injector(s) or loss of compression in one or more cylinder. The live data will indicate which cylinders are misfiring narrowing the cause of the problem significantly.

Your Answer

Ford F-150 Experts

  • #1
    OJ
    Reputation
    9,070
  • #2
    dandyoun
    Reputation
    4,580
  • #3
    tennisshoes
    Reputation
    3,130
View All

Related Models For Sale

Used Chevrolet Silverado 1500
2,264 Great Deals out of 168,222 listings starting at $1,000
Used GMC Sierra 1500
996 Great Deals out of 66,241 listings starting at $2,495
Used Ford F-250 Super Duty
312 Great Deals out of 45,312 listings starting at $1,700
Used Dodge Ram 1500
358 Great Deals out of 10,824 listings starting at $1,500
Used Toyota Tundra
461 Great Deals out of 33,419 listings starting at $2,000
Used Toyota Tacoma
570 Great Deals out of 44,300 listings starting at $2,200
Used Ford Mustang
589 Great Deals out of 36,206 listings starting at $1,200
Used Nissan Titan
216 Great Deals out of 20,521 listings starting at $3,390
Used Chevrolet Colorado
266 Great Deals out of 33,981 listings starting at $1,900
Used Ford F-350 Super Duty
344 Great Deals out of 25,132 listings starting at $2,488
Used Chevrolet Silverado 2500HD
332 Great Deals out of 30,020 listings starting at $3,500
Used Chevrolet Tahoe
718 Great Deals out of 41,409 listings starting at $1,995
Used Ford Explorer
908 Great Deals out of 67,921 listings starting at $1,495

Used Cars For Sale

2018 Ford F-150 For Sale
61,986 listings starting at $21,482
2017 Ford F-150 For Sale
128 Great Deals out of 60,362 listings starting at $17,990
2016 Ford F-150 For Sale
140 Great Deals out of 7,956 listings starting at $16,995
2015 Ford F-150 For Sale
364 Great Deals out of 11,527 listings starting at $15,591
2014 Ford F-150 For Sale
501 Great Deals out of 14,430 listings starting at $9,999

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.