I have a 2005 5.4L. Im getting DTC for random misfire, 5 and 6 cylinder mis fire, misfire on first 1000 rpm.

This is what's happening:
- extremely long starting
- Acceleration is very slow, CEL will start to blink at that point (misfiring)
- Strong smell of fuel after start up and idle at a stop sign or whatever.
- Usually a back fire when accelerating from a stop light but not always.

This is what I've done so far:
- Changed all spark plugs last week ( Champion 1 pc)
- Changed Bank 2 Upstream O2 sensor
- Changed ignition coils on 2, 5, and 6, (problem proceeds)
- Swapped 6 and 7 fuel injector to see if problem follows ( it did not)
- Inspected and cleaned MAF sensor

The only other thing i can think of at this point is the #6 ignition coil plug is faulty BUT Ill unplug it and itll pop a DTC for it which tells me its indicating me unplugging it so im not sure on that one.
Can i shoot for resistance on it? if so does anyone know what it is?
Im pretty lost and running out of ideas. Im hoping its not a PCM, compression or worn cam problem. All help is appreciated !!! thanks!!

 

I have the same problem. Got #5 cylinder misfire so I changed the plug and coil pack on that hole. Now I get a diesel sound from the passenger side near the front of the motor. I am going to run to O'Really! today and see if they find another code.

I know it could be cam phasers, timing chain, VCT solenoid?? A number of things. But I hate chasing problems.

And it runs rough and the CEL is blinking if I drive it.

I have read of people changing their oil and doing 5-30 or 10-30 instead of the 5-20 and their problems going away due to oil pressure with the thinner oil. I dunno???

 

im even looking into doing a compression check for the #6.has anyone had this problem and troubleshot this far down to fix it?

 

Ohbucks, check out my post as well. Sounds like we may have similar problems. Let me know what you find.