Idles rough hesitates jerks around 60 km an hr untill u bring up RPMs

Tiny
BOOTY
  • MEMBER
  • 2008 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 190,000 MILES
Truck runs rough . Engine light is now on. Computer says cylin 3 and 4 misfires . Replaced egnition coils on 3 and 4 already. Also put new plugs in 2 months ago. Any more sugg thanks
Saturday, September 27th, 2014 AT 4:22 PM

1 Reply

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Have you replaced the two plugs with the new coils? Is the same code turning back on? Have you checked for vacuum leaks? These vehicles are known for a vacuum developing in a hose behind the throttle body that has a 90 degree bend in it. They dry rot and leak. Also, have you checked fuel pump pressure?
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Saturday, September 27th, 2014 AT 6:03 PM

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