diagnose my issues ?

[New POD]

Car is a 3.2 MV6 auto with a mega 176K on the clock. 
Recent service history shows a Cam belt at 161K, Breathers cleaned out at 168K, oil and filter, and air filter changed at 173k. 
There is an oil leak at the back of the engine. 

So on Saturday the aim was to drive 440 miles to Cardiff and back at the speed limits, and with cruise control on for 430 of those miles.    

Car starts a bit rough, but within a couple of miles it seems okay, perhaps a little unpowered, but on the motorway, at 70 mph it's okay.  All is fine until we get to the M50 which has a few inclines and I become aware it's running on less cylinders than GM designed it too.  I cure this by sticking it it sport mode to avoid the mega 2500 rpm flat spot. 
At Monmouth it's struggling to idle at the traffic lights, so I put it in Neutral and give it a rev. Clearly misfiring. 
I continue to Cardiff.  Park car, get pay and display ticket, and decide to move car 30 yards closer to my daughters student house.  Car runs on all six. 

Drive to Penarth for Chips, then Back to Miseryside, with no issues.  Fuel consumption averages 33.8 mpg for 455 miles. 

I ignore the car until Tuesday Morning, when I drive to Derby some 110 miles away. 

Again rough running to start with, and once on the motorway, it's clearly misfiring. Stop on hard shoulder. Turn it off. count to 10, restart. Runs fine for 55 miles, until stoke.  Restart and it's all fine for the last 40 miles. 
 All fine this evening to drive the 15 miles to my digs. 

Now. I have some new plugs to fit - from main dealer (but postponed because torx fasteners and lack of suitable tools and life then getting in the way), so if there's oil in the plug cavities I'll find out then. Plan is to do that when (and If I get home) at the weekend. 

I don't have a code reader, although  my brother in law has one he's used on my old mk4 astra, but I would have expected an emissions warning light if the coil packs were failing. Plus I'd expect it NOT to be intermittent.  (The Mk4 astra 1.6 I had threw up a warning light when the coil pack was failing) 

Anyway.  Anything else to look at?  

also anyone near Derby or Nottingham (My digs are next to Ratcliff on Soar Power Station) that might fancy laughing at it one evening)

[Dead_E23]

I have consulted the infallible* tealeaves:

 

 

and they say it's either fuel pressure or chlamidia.   Try changing the filter and see if it anything improves.

[Royale80]

Coil packs failed on my 3.0 Omega.

There were no engine management lughts on.

 

Steve

[DodgeRover]

Coil pack and or crank sensor to be sure if it's not had one in the last 15 minutes. Neither cause an EML light

[Dead_E23]

Googling for MV6 misfires suggests that the plug leads don't last forever on these engines either. 

[DodgeRover]

Bosch brand plug leads used to be available via ebay

[New POD]

Googling for MV6 misfires suggests that the plug leads don't last forever on these engines either. 

 

2.6 and 3.2 do not have plug leads, but 6 mini coils above the plug (I think)

[xkjagnz]

Sounds very much like crank position sensor breaking down, when it goes completely you'll be stuck! (sometimes will restart and run after a 10 -15 minute rest)

[New POD]

Sounds very much like crank position sensor breaking down, when it goes completely you'll be stuck! (sometimes will restart and run after a 10 -15 minute rest)

 

I probably should have a spare ready for the RAC man to fit for me?

[omegod]

Either one of the ( two, one for each bank) coil packs failing or rocker cover gaskets spewing oil into your plug wells, i'm doubting crank sensor as it usually just stops them running completely

[red5]

Rocker gaskets get my vote. If I'd had some money for each one I'd done...I'd have, well, some money.

 

Fairly sure one type used to be a rocker cover change rather than gasket ^^

[lisbon_road]

If breathers have been cleaned, likely it/they were blocked, hence fair chance the rocker cover gasket has been pressurised for a while and might be damaged.

[New POD]

You can draw your own conclusions from the pictures.

 

There were codes

 

P0170 
P0300 
P0302
P0304
P0306
P0420
P0430
P0650 (only on two pedal trick) 

 

I should have replaced Plugs as soon as I got the car some 12K ago.

 

I would have noticed the oil leak from cam cover on 2,4,6 side.

 

Since Sunday I have done 200 miles having reassembled without fixing leaking cam cover or replacing very dodgy looking Coil packs, but having cleaned and dried it all up using brake cleaner, before reassembly.

 

Since then there have only been 2 codes - Both P0170 Fuel Trim. But only on Monday and Tuesday. I will check again when I get home tomorrow.