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[kevinminton]

Hi folks - any help or ideas with this new prob please?
2.6 auto, 90k miles. Misfire started just today - engine intermittently goes down to 4 or 5 cylinders - sometimes under light load &  small throttle when moving off, even when just idling in D - shift to N and it's OK again. Also there at 50, 60mph on Mway, and at full throttle.

Did "paperclip test" with brake and throttle (thanks to OOF!) - got 0030 - "multiple misfire detected".

Engine temp all OK, and when not misfiring car runs as expected. There is no particular set of conditions / driving that will prompt misfire, or avoid it!

One other symptom thay may be related - for the last week or so has not always been starting instantly  - needs to or three revs instead before firing up.

Breathers cleaned & cam covers where changed 3000 miles ago - a proper job done by EP and LK - no hot oil smell / leaks. Fresh tank of Sainsbury's petrol during the day. No water or other foreign matter visible under bonnet.

Any suggestions will be welcome - thanks!

Borrowed Daughter's car to drive to London just in case it got worse - I'm not being rude but gotta go now!

[Martin_1962]

Plugs

[Del Boy]

Plugs

Yup agreed, could be leads too 

[feeutfo]

strange,  :-/ could be ignition, could be fuel, any oil in plug wells? Cracks in coil packs? When was fuel filter last changed?

ignition issues usually fairly consistent.....arent they? :-/

[Omegacraig]

I would say definatly check all the ignition side out, plugs & ht leads first, if they are all clean and ok it could be the dispack i recently replaced mine trying to sort problems with my lpg system, and i found several bad connections on the dispack (that lead to the contacts corroding and so becoming even worse) we would never have discovered otherwise.

A common ignition problem on the v6 omegas is where the rocker box leaks oil and so the plug holes fill up causing a poor spark and degrading the ht leads.

[VXL V6]

Plugs

Yup agreed, could be leads too 

No leads on a 2.6 or 3.2

[Omegacraig]

are the 2.6 & 3.2 individual coils on the plugs?

[The Cambelt Kid]

No leads on a 2.6 or 3.2

DITTO, beat me to it by 6 mins 

[feeutfo]

are the 2.6 & 3.2 individual coils on the plugs?

2 coil packs. 1 per bank. 3 plugs per pack.

2.2 4 per pack

[MikeDundee]

Sounds exactly the same problem as I had last year coming back from Newent, ended up changing both coil packs, then changing all the spark plugs........

[kevinminton]

Thanks all for your ideas. On the basis of the prob affecting more than one cylinder, I'm going to go to the coil packs first and see what's visible. Then plugs out, etc

Will let you know how I get on (this pm)

[Del Boy]

Plugs

Yup agreed, could be leads too 

No leads on a 2.6 or 3.2

That is a very fair and brilliant point 

[kevinminton]

So ... took Rh coil pack off - some condenstaion on lower side, some oil / muck on coil pack, rubber insulators and in plug wells. Cleaned everything up with carb cleaner - insulators were breaking up in my fingers as I was doing it. Some hairline cracks also in coil pack - now I remember EP warned me about this!

Re-assembled - and all signs of misfire gone! (for now). I guess the higher under-bonnet temperatures at this time of year accelerated the deterioration of the insualtors. Didn't do other side yet - still working out how to get cable tray out of the way.

So, I,m now looking out for coil packs and rubber insulator things. Thank you everyone for your advice which led me straight to the problem.

Kevin

[feeutfo]

glad you found the problem.
Are the pacs likely to be original?
How many miles they done?
Just trying the guess the life of the part.

[kevinminton]

90,000 & original - but this is not a fair assessment of the life of the coil packs, 'cos until 3000 miles ago, they would had contamination by oil from combination of blocked  breathers & leaky cam covers.  So the insualtors had maybe 10k miles of hot oil bath.