Engine Warning Light!

[daverichardson]

Went for a 30 mile drive out today and parked up no problems
Upon return and starting a strange noise and vibration as I reversed
Drove in the car park and as revs picked up noise / rumble went away
Then the engine symbol warning came up on the MPH gauge and flashed intermittently
Followed about 10 minutes later by the Go to dealer fault light in the middle screen
Parked up again and put the diagnostic on it and Cylinder 7 misfire came up.
I reset it and drove home.
No more Go to the Dealer but all the way home the engine symbol (in the MPH dial) flashed intermittently
and went off again only to keep on returning and flashing
It did not seem to matter what revs I was doing it was random
Noise / rumble is still apparent at very low revs < 1000rpm
Parked on my drive, had some lunch and off out to give it a look at again
Any thoughts would be appreciated (QPV EXEC GT AUTO)

 

[CatmanV2]

Sounds like a misfire. Intermittence would mean I suspect electrical fault. Broken plug or coil pack maybe.
Check the codes again, and if it's still 7, try disconnecting / swapping with another to see if it moves.

Pretty random thoughts though

C

 

[daverichardson]

Another look confirmed the original scenario.
Codes that came up were
P0300 Random Cylinder Misfire
G7E8
G7E9
Cylinder 7 and 8 misfire
Sat on my drive it idles ok, but when I move the noise returns and it is slow to pick up and the engine light intermittently flashes

 

[StuartW]

I agree with the cat, sounds like a damaged plug, coil pack or the fragile cabling around the coil. With it being intermittent, I would suggest the coil pack or cabling rather than the plug itself. Nothing worse than an intermittent fault though - good luck

 

[daverichardson]

Pretty much my thoughts too guys
Which raises several questions
Where do I source coil pack leads?
How much?
Same for plugs
and
is it an easy job?
d

 

[CatmanV2]

Eurospares.

Coils are about £42 for the 4.2, plugs about £16
http://www.eurospares.co.uk/partTable.asp?M=3&Mo=754&A=1&B=47223

C

 

[daverichardson]

Thanks mate
I will check them out
one plug (and the coil assembly) in particular looks difficult to get at - right under the bulkhead
Any experience in changing them?
d

 

[daverichardson]

Step 1
Ordered the plugs today for delivery tomorrow
What is the order of the cylinders, 7 & 8 came up on the diagnostic so physically where are they?
Nearest the front or under the bulkhead near the cabin?
Left or right as you look from the front?

 

[philw696]

On a 4200 they are numbered on the wiring harnesses.

 

[CatmanV2]

Thanks mate
I will check them out
one plug (and the coil assembly) in particular looks difficult to get at - right under the bulkhead
Any experience in changing them?
d

None at all, sorry.

C