Truck runs rough and sounds like a diesel

Tiny
CHRIS BURGE
  • MEMBER
  • 2004 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • 180,000 MILES
We all know these 5.4 liter Ford engines do not last, but I was hoping you could give me an idea what is going on. I am a mechanic and a pretty good at diagnosing, but the truck will run great one day then run like a diesel seconds later. 30,000 miles ago it had all new plugs and coils, along with new cam phasers. I have the codes p0011, p0012, p0300 -p0305, p0340, p0344, and p0345.
I cannot grasp why there are so many misfire codes, unless it is something internal like a VCT solenoid, timing chain, or CMP sensor. I really do not know where to start.
Do you
have the same problem?
Yes
No
Thursday, March 16th, 2017 AT 4:53 PM

2 Replies

Tiny
HMAC300
  • EXPERT
You are going in right direction see pic to check VCT actuators maybe the problem. There is a TSB for later model ford trucks for this, but shown is test and what to check. Then check fuel pressure for misfire if you still have them as well as doing freeze frame to read sensors to see if one low or out of spec. See picture.
Was this
answer
helpful?
Yes
No
Friday, March 17th, 2017 AT 7:10 AM
Tiny
CARADIODOC
  • EXPERT
We can forego the common stuff since I am sure you have done that already. Let me shift your thinking in a different direction. Look if your engine has an EGR system with eight individual tubes running to the cylinders. Some of these systems operate by allowing a measured amount of exhaust gas flow, then that is supposed to divide up equally among all eight cylinders. Over time one or two tubes become blocked with carbon. Those cylinders run especially fine because they get only fresh air. The other cylinders get too much EGR, and eventually misfire. As this progresses, there may be only one or two cylinders still getting EGR flow, but they are getting that which should have gone to other cylinders. It is the cylinders with clear EGR tubes that misfire, and those with blocked tubes run okay. Since EGR shouldn't take place at idle or low speeds, the misfires do not show up there.

If I am off-base, consider re-posting your question, as this one has gone "off the list", and none of the other experts will see it or have a chance to respond.
Was this
answer
helpful?
Yes
No
Friday, March 17th, 2017 AT 11:05 AM (Merged)

Please login or register to post a reply.

Recommended Guides