V8 rough idle/run all of a sudden

[brougham]

D2a, new 4.6l motor (8000kms), injected LPG.

All of a sudden started idling badly, both in lpg or petrol. If I idle in drive, it's that rough the battery light flickers on an off.

It's now even running a bit rough at speed. Although if I boot it, it kicks in and purrs away.

Any ideas? Seems to be getting worse.

Nathan

[bee utey]

I would suggest you have a failed inlet manifold gasket. They really need to be retightened once after installation, hard to do on a D2, I know.

[brougham]

It's had the 1000km post overhaul service and checkup by the same
LR specialist that did the changeover. Would've thought they'd checked that.

Anyway to check it myself if it's failed ?

[bee utey]

You can't check the inlet manifold bolts on your D2 without removing the top section of the manifold first (20 or so bolts, some well hidden). The bolts in question hold the lower half of the manifold to the cylinder heads. I have seen plenty of loose inlet manifold bolts on earlier engines where at least you can see/check/tighten them without major dismantling. I'm repairing one like that right now, on a D1.

[brougham]

Is it bad if it's blown? As in engine rebuild bad?

[bee utey]

Is it bad if it's blown? As in engine rebuild bad?
No its a new gasket and about 2-3 hours for a competent mechanic. I strongly suggest you visit your mechanic and let him diagnose, I am only guessing by experience, he will be better placed to find the exact problem. It could be just a loose hose somewhere. Have you listened to the engine with the bonnet up? Looked for anything out of place? Any unusual sucking noises?

[brougham]

Yeah did that this evening. Couldn't hear anything amiss or looking odd. Fluids all good, no oil drops or anything (love new motors).

I did have a thought it was the computer telling me it's time for a service (my ford focus used to magically run rough exactly 500kms before each scheduled service).

[brougham]

Hmmm. It's rough at idle, and driving at speeds up to 80km it runs badly almost as if it was starving for fuel. Above 80 and under acceleration its fine.

It also comes and goes at times.

Could it be a vacuum hose leak maybe?

[Krayzie Keegs]

I would have a quick look at your plugs I was getting a rough idle a few weeks ago and yes boot it in the arse and off it go's the rear lead had failed but picked up when ran quick,

have a look at the air intake if you are getting too much you will not get a good burn and will be rough

if not pull it over and get it looked at but the people who put it in