Every car has one (or more in some cases) - the signature issue that every owner dreads.

Having had our Mini just under a week and in that time driven it in most conditions, I thought I could feel an intermittent misfire, often when beginning to pick up mid-range pace (but that might be because it's easier to detect when accelerating smoothly on a DC or motorway). Anyway, I obviously went on a quest on the Internet and Mini forums.

Turns out, there is a fairly significant and serious issue with coking on the N14 1.6 turbo engine, which can lead to major loss of performance, economy and potentially damage.

Because it is a direct injection engine, procedures like Terraclean don't touch the relevant areas and until quite recently, it was a major strip-down job to remove the nasty crud from the valves and intake ports.

For quite some time, Mini/BMW did not acknowledge that there was an issue and were routinely charging £1000 for a strip down and decoke (yikes!).

Apparently now it has been recognised and there has been a wave of so-called "walnut shell" decoking machines installed at BMW (and other) garages. The reason for the name is that it transpires that walnut shell granules are the bees knees for leaving your engine sparkling clean without damaging any parts.
The new treatment can be had for between £190 and £300, depending on who's bending you over.

The next step, following a decoke is to fit a "catch can" to filter the nasty oily vapour, leaving the gunk to condense into the bottom of the can, which then needs regular emptying.

Many Mini owners are pretty pissed off about the situation (it can become a problem from as little as 10,000 miles) and I must admit I'm a little concerned myself, even though I've not yet identified a definite problem. I don't think there is a snowball's chance in hell of claiming anything either on warranty or from the garage.
If I were to get it diagnosed by a specialist and there was a significant problem, does the panel think I would have a case under Sale of Goods legislation?

So, I'm now adjusting to a new set of paranoia rules, wishing I had a budget of more than £zero to investigate.

It is still a great little car, though!

That's a interesting situation Jim and I doubt straight forward to diagnose without a reasonable cost. Maybe a conversation with the garage outlining your concerns with what you have found out would lead to the garage checking it out further as a good will gesture?

I just spoke to a really top bloke called Dan Turner at Turner Race Developments in Stroud; he reckons that as long as the engine management light isn't coming on, the garage won't touch it, as it's more of a wear and tear issue. The comparison he made was with a slipping clutch - it may not be perfect, but it still works...

You're right about diagnosis being difficult. Dan offered to put a camera in to check, but apparently you need to take a lot of parts off before you can examine the relevant bits!

I'll just keep a watch on it for now and see what happens...

There may be something in the goodwill pot, as we have just had to get a garage to sort out the suicide door, which was broken when we bought the car, but they have paid. They offered either to fix it or knock the price down £100. We opted to have them pay to fix it; the bill from the garage was £104!

Ever looked at 1320 mini, they know their stuff.

As long as it's not the death rattle. I took a friend's company car Cooper S out for a blast (she was stunned how quick it went when driven properly). A week later she started to get running issues and it turned out to the the cam chain tensioner (death rattle) - fortunately her company lease sorted it ( along with MINI) - as I was feeling a bit guilty.

Isn't the cam chain tensioner problem part of a recall on the turbo engine? Might be worth checking:)

I would try and take the car back as this could be a nightmare. There was an interesting piece on the sale of goods act on Martin Lewis itv programme a month or 2 ago( I think 2 episodes covered a 4 wheel drive that had a spanner in the turbo, google it and watch. Eventually the financial ombudsmen had to be involved.

I think investigating the problem without excessive costs may not get to the bottom of it.

I would be upfront with the garage and hint to them that the misfire really affects the drivability of the car and it could be more costly to try and get it fixed and result in several claims.

Look extensively into the return of a vehicle and arm yourself with the facts.

Thanks everyone. I don't think it's anything to do with the timing chain/tensioners - there is certainly no chatter or rattle at any revs. Unfortunately, although I have the stamped service book (the car had the 5-year "TLC" package), there is no paperwork to accompany it, so I've no idea if any additional work has been done (recalls, etc). As far as I am aware, there hasn't been a general recall on anything engine-related, but I may be wrong. As I understand it, the warranty would cover a failure related to a component like a timing chain, but not a gradual decline caused by coking.
Part of the problem is that I'm still new to the car and our local roads are so twisty, bumpy and narrow that it is impossible to be certain that I'm not imagining the misfire. Especially coming from the Merc; I can hardly imagine 2 more different driving experiences!
I did tell the garage that I suspected there was a misfire before I had looked into it, and the guy was adamant that if it became problem I should bring the car back. Remains to be seen if he's as good as his word...

Thanks for the tip about 1320 Mini, Richard24 - I've signed up to the site. Shame we no longer live in Cambridge...!

Jim - if the work has been done with MINI, it's normally possible to ask them to print out the history.

The ride is incredibly harsh in a Cooper S - especially if it's still running the horrible run-flat tyres.

MRS, I spoke to Dick Lovett (where the Mini originally came from) and they said they can send me the records of the services that have been done, but nothing else. I said I'd got the service book and they said they wouldn't be able to send me anything to add to that. Bit disappointing...

I spoke to the garage we bought it from today and they agreed to phone the previous owners to ask for the manual and any bills, etc. Fingers crossed...

The ride is ridiculously harsh, especially after the E320!, and it is on the run-flats. Unfortunately, as it has no spare wheel, despite having the full well in the boot (you can buy one with a fitting kit for £100-ish), I can't change away from them yet. The fronts are looking a bit second hand on the shoulders, but the rears are pretty new, sadly. If I can find a way to ditch them for something more compliant I will.

Anyway, here's a couple of pics I took in between sleet showers today (like you've never seen one...!)

When I enquired about print outs from the OPC where my Boxster was serviced, they gave them to me, but had to chop off the top off each one as it had the previous owners name and address on it, despite me buying it from and picking it up from, the previous owners home address.

All very daft but data protection kicks in I'm afraid.

Sadly I believe all minis are riddled with problems, early ones had electric power steering issues and I believe they liked to get warm.
Later ones I know of a myriad of little niggles that alfa would be proud of.
I hope it's a bit of nothingness Jim as your luck with cars seems to be pants!

Cheers, Big Muzzie, for those optimistic words!

Looks very smart, Jim. My dentist would kill me if I got a Cooper S but it's fun to hoon around in someone else's. I've often tested at Knockhill with the MINIs and they are blindingly quick through the corners. White Lightening is faster on the straights though - it's a situation that can lead to frustration all round.

As you say, chalk-and-cheese from the E320 - it's a shame that one had so many problems. My W210 (2000 model) was a rust bucket for a while (though we eventually worked our way through it - at Merc's expense) and the trim on that was rubbish too - but mechanically it was almost faultless. One leaking injector for which the local engine place re-cut the seat in-situ. The W211 had a broken front spring and rusty brake pipes. My current one has been fine except that the tailgate doesn't open fully automatically.

Is it like a Tardis in there Dr?

It was a bit negative, sorry!

I do seriously hope it's ok for you. Have you tried running on super unleaded?

We will look back on the E320 with nothing but fondness and respect - for not that much money it got us (and a shed-load of stuff) home from Spain so effortlessly and comfortably. Since then it has carted furniture around Stroud and made 2 return trips to Cambridge and one to Leeds. I gave it new tyres and had a faff with the brakes at the beginning but other than that it was awesome. Most of the kit, trim and bodywork was in great nick and - remember it had done 214,000 miles when we got it and 220,000 12 weeks later - we got a grand back for it on trade-in without spending a penny on the massive and essential repairs.

Brilly1uk - you know what, with the seats down we got a 80x80x100cm chest of drawers in it yesterday, so it's not bad, even if it's nae f***in' Tardis!

Big Muzzie - virtually all of our vehicle woes can be put down to a lack of money - either in terms of buying cheap and suffering the inevitable consequences as other people's neglect or old age runs its course or not having enough to spend on preventive work and contributing our own neglect. We try to strike a balance, but the truth is, you don't get owt for nowt.
Hopefully, with this car we can afford to maintain it properly (I'm not as scared of it as I was of the Merc!) and maybe our "luck" will improve... I'm sure it won't be perfect, but hopefully it will do the job AND put a smile on our faces!

It IS a tardis!
Hopefully it will serve you well and the go kart handling should put a smile on your face.

I'm sure you'll enjoy it Jim, If you haven't already are you going for a warranty?

It does make you smile for the way it whizzes around, but as MRS pointed out, your smile might be missing a few teeth!

Missed your warranty comment BM - yes, we got a 2-year warranty with the car for ~£100. According to the terms it covers "absolutely everything that doesn't ever go wrong and pretty much nothing that fails".

It specifically does not cover decokes, but surprisingly, it does cover "timing gears, chains and tensioner", which is a relief, given MRS' comments above...

Jim, I had a 57 plate cooper S with similar problems. I feared the dreaded coke issues but took a punt on fitting a new set of plugs myself and the issue disappeared. Good luck.

Thanks, Bilbo, that might be the first option. It's still not a bad misfire, but every time I think I've imagined it, it recurs!