Flashing check engine light Discovery 3S 4.0 V6

[Julian B]

Hi folks. Now that I have organised paypal I am a paid up member!

I need some help regarding my Discovery petrol V6.
I bought this for a steal with a cooked gearbox and replaced the ageing but reliable forester.
It does half of its time on the highway between 80 and 100km/h so isn't just an airconditioned urban box.

I returned from a highway run and the morning after this I went to start it and promptly got a flashing check engine light (CEL), and an idle that was just decreased and a little rough feeling. I did not drive but a quick rev revealed a smooth sounding motor above idle.
I have a cheap OBD scanner, which shows faults:
P0300
P0301
P0303
P0305
P0316

This combination suggests a misfire on all cylinders on the driver's side bank. For others reading this in the future from other countries, with the hood/bonnet open and staring at the motor this would be on your left.
Standing behind the car it smells like fuel thus confirming a probable misfire.

My thoughts:
- Each cylinder has its own coil on this motor
- The oil looks good, no cream
- The coolant looks good no oily residue and there is no smell or steam ****ing out the exhaust
- Is it an electrical fault?
- Vacuum?
- Strong starter sound and no hesitation to starting

What have I done?
So I pulled the plugs. They looked original with a gap ~2.5mm but not black/green/burnt. Changed with genuine plugs and hard reset the same issue.
MAF sensor wire cleaned with CRC MAF sensor cleaner. No change.

Throttle body previously cleaned following a CEL.
Air filter replaced 3 months ago.

What causes a sudden change to a whole bank, without warning? I don't want to drive this to fry the catalytic converters, but side of the road revving at cold feels smooth so what is going on?

Thanks,

[MonLand]

Weird. But I would google the same symptoms since this is a Ford engine common used on a lot of trucks. For example: 4.2L V6 Misfire Mystery - Ford F150 Forum

[bee utey]

A cylinder with a vacuum leak on the inlet side will still push out unburnt fuel, but only at idle. So probably safe for the short term. Failing inlet manifold gaskets are common on various engines and can usually be found by using a piece of hose as a stethoscope. If you can dribble some water along the manifold edge any sucking noises would lead you to the leak site too.

[Disco-tastic]

Don't they have individual ignition coils? Could it be a faulty coil or lead?

I don't know if you can do the "pull off a lead til you find the faulty cylinder" thing with the modern motors but would that be worth a try?

[PhilipA]

You maybe should google Explorer P0300. There are lots of instances there.
Here is one,

the p0300 code means multiple cylinder missfire. That could be the coil, but you have ruled that out. Next would be the cam sensor, bad or blocked EGR ports, or bad O2 sensor. Normally if its the O2 you will get that code. I might have a tendancy to check the cam sensor and EGR prior to looking into the CAT... but that is a possibility. Hopefully not on a 2004. Got bad gas in your area ??

Regards Philip A

[101RRS]

Just get the codes read by a proper machine and it will most likely tell you exactly what the issue is and what cylinder etc is playing up.

[Julian B]

A cylinder with a vacuum leak on the inlet side will still push out unburnt fuel, but only at idle. So probably safe for the short term. Failing inlet manifold gaskets are common on various engines and can usually be found by using a piece of hose as a stethoscope. If you can dribble some water along the manifold edge any sucking noises would lead you to the leak site too.

Gasket was a thought, and I like your observation about idle only. Sudden failure though?

Don't they have individual ignition coils? Could it be a faulty coil or lead?

I don't know if you can do the "pull off a lead til you find the faulty cylinder" thing with the modern motors but would that be worth a try?

Each cylinder has own coil... Sudden failure on whole bank.

You maybe should google Explorer P0300. There are lots of instances there.
Here is one,

Regards Philip A

Nice observation. Where are the sensors described here on the 4.0 engine in my car?

Just get the codes read by a proper machine and it will most likely tell you exactly what the issue is and what cylinder etc is playing up.

Anyone in Adelaide got one and can swing by a stranded enthusiast?

[Disco-tastic]

...Each cylinder has own coil... Sudden failure on whole bank...

Sorry, just to confirm, but its multiple cylinders that are misfiring on one bank? Not just a single cylinder?

I have the same motor so am following this in case I ever have the same issue

[Julian B]

Sorry, just to confirm, but its multiple cylinders that are misfiring on one bank? Not just a single cylinder?

All cylinders on the drivers side are misfiring per the codes.

[Julian B]

Where can’t one find a manual for this motor?