I have a 2005 Dakota with 4.7 I am getting a miss fire code on # 1 changed the coil pack with # 7 still getting miss fire on # 1 moved the plug from 1 to 3 then installed a new injector still get the miss fire code I am not losing coolent so i don't think it is the head gsaket the truck has 90000 miles what should i be looking for or change next Thanks for your Help Don

 

Moved to the correct section.

 

Now swap the spark plugs (1-7).

 

If the plugs don't make a difference, then swap the fuel injectors. That one can get messy as you will spill fuel when you disconnect them. I don't recommend you do it alone. And make sure the engine is fully cooled down. Have lots of paper towels handy to soak up the fuel and a fire extinguisher.

 

depending on what plug you are using, make sure the gap is correct, I run the autolite 3923 plug, its a cooler plug then stock and gap is. 040,

 

Thanks for the help I will try the plugs first and if that does not work then the fuel injector Don

 

one other option, and its not a good one, the head gasket maybe leaking into the cyl

 

I had a misfire on my 07 4.7 with 180k and I couldn't figure it out so I finally just bought a 4.7 from a 05 1500. Finally got around to tearing the old engine apart and there was a rocker arm that somehow fell out of place. No idea how it happened yet. Still requires more digging that I haven't really had time for but I would suggest pulling the valve cover and checking.

 

And if none of that works - compression test. Then it's onto valvetrain issues - I did all this on my mothers car and everything was good, spark, fuel, compression. Found a rocker arm had come out of place somehow, she had some bad gas and had to change the fuel filter also. I think there was detonation from the bad gas that sent the rocker off the valve.

 

If you want to swap injectors, pull the fuel pump fuse and crank the engine over to bleed the pressure down. You'll still get fuel from the fuel rail but it won't be under pressure.