umoms

I been driving my 03 Expedition 122k miles for a while and all of a sudden the CEL starts flashing and the car is misfiring. I went and scanned the codes and got


p0307 Cylinder 7 Misfire Detected
p0304 Cylinder 4 Misfire Detected
p0174 Bank 2 System Too Lean
p0171 Bank 1 System Too Lean
p0316 Misfire Detected on Startup (First 1000 Revolutions)


I erased the codes and the same ones came back. What do you guys think it is? Replace Cylinder 4 and 7 coils?

CatSkinner

Bith banks are running too lean, you may have weak coils, but I'd be wondering what your fuel pressure is running at and if you have any vacuum leaks first.

__________________
Prius repellant, just add gas.

R.S.LOGAN

Swap the coils and see if it changes cyls ?

Common Symptoms of a BAD
Ford Coil-on-Plug Ignition Coils

This is not the most definitive list on the subject, but does cover the majority of symptoms I've seen on this type of Ignition System:
1.Misfire Codes that light up the CHECK ENGINE LIGHT (CEL) on your Instrument Cluster.
2.Misfire Codes: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308.
3.Engine Misfire that DOES NOT light up the CHECK ENGINE LIGHT (CEL).
4.Smell of unburned gasoline coming out of the tailpipe.
5.Rotten egg smell coming out of the tailpipe. This is due to the unburned gasoline from the misfiring cylinder over loading the catalytic converter.
6.Really BAD gas mileage.
7.Lack of power as you accelerate the vehicle down the road.

Hamfisted

How old are the sparkplugs and fuel filter? Might just be a good opportunity for a complete tuneup, to include a new fuel filter. Clean the MAF too. But yes you can probably count on replacing at least those two coils. The fuel filter is a Motorcraft FG-1063. Use Motorcraft sparkplugs and coils as well.


-Mike