RR 4.6 HSE Miss fire (possibly)

sounds like oxygen sensors look around online for equivalents, the LR ones are ridiculously expensive.

I had similar symptoms on mine but it started overnight, turned out to be the crank position sensor, well not the actual sensor but its mounting had broken/cracked. Trouble was the gearbox had to come out to fix it. Hope yours is cheaper!

Gaz

Sounds like airflow meter but could also be coil packs .

Sounds exactly like a fault I had. Couldn't find a fault at first, and all plugs seemed to be working as they all looked fine. After a few days the "lumpi-ness" got really horrible and it was obvious it was only firing on 6 cylinders. Was one of the coil packs had burnt out, had a black hole in it and wasn't generating any HT. Unfortunately at the time I couldn't locate a second single coil second hand and had to get the entire pack replaced. Strange enough, the Check Engine lamp didn't light. Exhaust smelt very rich with the unburnt fuel passing from the 2 cylinders, and probably didn't do the cats/lambda sensors any good either.

Alan C

Exactly my problem. Lumpy tick over, under load one hell of a miss- fire, smell of fuel and terrible fuel consumption (even worse than normal!!!) when i replaced the leads I found the coil pack lose at the back of the engine bay, not bolted in at all!!!!!! bolted it back on the intake manifold.Both my cats have gone and are rattling and this happened at the same time that the lumpyness started, so, you could be right. Trouble is, how to find which coil is knackered or simply replace the whole lot?

Where to find a replacement coil pack for under =A3250?????

AlunP

Where to find a replacement coil pack for under £250?????

AlunP

Is it Gems or THor? The coils are different. If Thor, the management system logs misfire codes to tell you what cylinders are misfiring, this aids diagnosis of which coil pack has failed. Badger.

It is a '95 with four seperate coils in a row, each coil has two HT sockets. The annoying thing is that when on tick over I have removed each injector electrical lead to detect the mis-fire but all cylinders are firing, so, it is breaking down only under load. Makes it even harder to detect!!!! I will also look at the lambda sensors as well, as I believe if they are U/S a similar effect could be caused?????

AlunP

RESOLVED...................today while checking all leads and connections to the coils etc the mis fire was getting worse. After a coffee the engine would not start at all. No spark and no injector pulse. Noid plug proved no signal to injectors. After scouring the engine bay with a torch I found that the lead connecting the crank sensor had worked loose and finally fallen off. Plugged back in and I have my engine back. No misfires at all and pulling like a train. a little lumpy in places but I know the exhaust lanbda sensors are iffy......so, a simple loose connection and days of anguish....just goes to prove something.......

AlunP

Nice one, ahem, don't say I didn't tell you.... I thought the symptoms were familiar!

Sadly I sold my P38 today, withdrawl symptoms already..

gaz