Mine is back. P0307. With a vengeance. Worse in town, if I get on the expressway right from cold, no problems. But puttering around to work/bank/parts store/etc its noticeable.

Will pull plug today and see what's what.

This truck is going to up my Rogaine bill. a lot.

 

@zeroone - that plug is worn out. replace it. See how the electrode is down to a point? That's not good.

Time for plugs-n-wires...

- dc

 

Changed plugs on Monday and today is Thursday and codes aren't back yet!...but, I've only driven about 40 miles so I cant claim victory yet.

 

Mine did that. drove great for a week when I swapped plugs.

Then it came back, which led me to swap wires.

I got 350ish miles out of it before it came back.

Now, I am going to scratch my head and hope something happens next..

 

Thanks altdisco, I wasn't sure and was was just totally glad that the plug wasn't steam cleaned.

 

Well, in the spirit of seeing this fight through to the 10th round, here is my latest update:

Truck runs like crap. SES light flashing, etc, etc. Misfires still on #7, threw one on #4, and has catalyst damaging level misfire.

I'm heading to Advance to clean the MAF today with some of the good stuff, and will post back.

One code popped up for my downstream O2 on the passenger side, but lets face it, that sensor doesn't really do anything.

Next up for me after MAF is O2 sensors. I'm not looking forward to that job.

 

This misfire is not so hard.
You changed the plugs. the wires.
Only #7 misfires.

It is a valve hanging up once and a while in the head.
That is causing the misfire.

Valve is not coming down.
I would replace the valve springs on #7 if you can.
Probably have that head pulled and do a valve job on it.

Well then you may as well have all the headgaskets done.
and since that is so expensive and there is risk to damaging the engine
with new head bolts torqued and all that, maybe just put up with the misfire.

I have heard that you can put compressed air into the cylinder and hold up the valves to replace the valve springs.

I would let an expert do that.

Land Rover Valve Jobs - Erik Burrows.com

 

Valves may well be in order.

However, 2 new codes this morning (from driving yesterday) are P0103 and P0112.

Cleaned MAF, reset codes, will see. Next step is MAF replacement.

#7 would make sense on a MAF issue due to its location - can be starved for air.

Also, motor doesn't misfire when cold, only really pops up after 20 mins of driving or so, making me think that electronic issue to do with IAT sensor has something to do with it. (p0112)

If I have to deal with valves, I'll go ahead and yank the heads and do HG's, the truck has 75K on it, and is 13 years old, but no signs of HG failure as of yet.

More to come....

At least it's not like the Ducati Desmodromic valve system - look those up if you want to see PITA valve adjustment! But man, when they run right, wooooooooo.....so sweet.

 

Update:

Misfire is still there, engine running on 7/8 or 6/8 cylinders.

Pulled #7 plug today, and there is pretty extensive dry carbon fouling on it after under 1000 miles of driving.

Will pull another just to compare.

have MAF on the way, and I have probably smoked the Cat out of this thing. Oops.

Running very rich, just trying now to figure out WHY??!!

If MAF doesn't cure, I'll pull O2's.

Also - Ultragauge is not picking up all the codes, had a friend at a shop put his nice matco scanner on it, and it threw P0304, P0307, P0112, and P0300.

But at least the Amigos are gone.

Anyone want to buy a rover?

 

Back again. Porcelain helps me think....

Here is my current diag, based on what I've gathered - will be able to test and confirm later this week.

I think that the failed MAF caused the engine to run rich enough to dry foul several plugs, and they are now carboned to the point of no repair, even with cleaning them with brake cleaner.

So, to fix this, I'm going to replace MAF, then a BRAND NEW set of NGK plugs.

Then I will burn a sacrifice to the rover gods in my backyard, wearing a radiator hose and a loincloth. Suggestions welcome.

Hopefully that fixes is.