Hi

does anybody else have a misfire on 06 RRS supercharged when its cold .when its warm it runs great.

Hi, did you sort out your misfire ?

Hi
no just run it like it is doesn't seem to make any difference still runs nice when driving and no hesitation when accelerating.

Ok, just that mine has started misfiring on start up when cold , it causes the car to judder in either reverse or drive , I have to take it out of gear, Rev it up , put it back in gear and it seems to be then ok , misfire gone no more judder , until you leave it ,say overnight and misfires back !

that's a bit different to mine it will go along without any shuddering on tick over. suppose you got to start with getting it plugged into the computer.not losing any coolant are you ?

No loss of coolant , why do you ask ?

No codes or check engine light ? How many miles ? Were plugs ever changed ? Try cleaning mass air sensor ...

hi there.

Worth changing the spark plugs first if they have not been changed for a while.

Failing that get your codes scanned it is most likely is a coilpack starting to fail. Should show a code stating low resistance on coilpack or similar.

New plugs fitted about 3 weeks ago ! I have a Gap IID tool and nothing is showing up even after turning off the engine whist I feel the misfire is happening ! I will reiterate the symptoms: first thing in the morning start the car put into reverse and whilst reversing the car seems to be juddering as though it's not firing on all cylinders , so I put it into neutral or park , Rev the car which seems to clear the 'misfire' it then seems to reverse fine and drive spot on until it's left again for say 8 hours and it occurs again !

Did that start right after the new plugs ? I'd use contact grease spray on coil boots and reseat them all again. If that doesn't make any difference maybe a bad plug was installed , or bad gap, or not torqued properly. Who did the plugs and which ones were used ? If it was a shop , I ask them to check the work again.

Hi if you have a good code reader you can go into the data stream and look up the misfire count , it should show all 8 cylinders , check the counts on each cylinder they should be around 0 , if one is showing high number's that's where to start looking , if the count goes above a certain percentage then it will put a DTC code but if its lower than the set percent it wont , it could be a possible clogged injector , there is a land rover bulletin about the injectors clogging up and to use BG 44K Fuel System Cleaner before replacing the injectors , hope that may help 2007 SUPERCHARGED HST

found the Bulletin

Reference SSM46917
Models LR3
LR4
New Range Rover
Range Rover Sport

Title 4.2/4.4/5.0 Gasoline Fuel Additive For Clogged Fuel Injectors
Category Engine
Last modified 31-Jan-2011 00:00:00
Symptom 499000 Basic Engine
Content Issue:
Fuel injectors clogged leading to potential problems such as poor running, poor fuel economy, excessive exhaust emissions, hard starting, rough idle, misfires and engine detonation.

Cause:
Poor fuel quality or fuel contaminants restricting the fuel injector flow rate.

Action:
Land Rover engineering now approve the use of BG 44K Power Enhancer Cleaner (which is sold in an 11oz/325ml can or bottle) on 4.2/4.4 AJV8 and 5.0 AJ133 Gasoline engine derivatives.
The above mentioned additive should be used in the first instance in an attempt to cure a suspected ‘clogged’ injector (misfire DTC maybe stored) rather than unnecessary replacement.

NOTE: Land Rover recommend only using the above product a maximum of twice between each 15K service. 2007 SUPERCHARGED HST

Thanks for that I will have a go !