406 Exec 2.0l Idling Rough/Chunky

[Xan]

Hi, I have recently bought a 2000 406 Exec 2.0l which is a beautiful car and is very tidy (it was the natural replacement for my trusty 405 auto that was recently a right off after 6.5 years). However it is not as smooth as it should be. Sometimes (but not always) the car has a rather rough idle which makes it feel like a diesel, it also seems sometimes to surge and drop back in power when driving. A friend describes it as a bit chunky. I have had it tuned and the chap was mystified by it. Apparently the ECU readings are all spot on, his thoughts were firstly a dirty fuel injector, or secondly the timing belt is out or lastly but doubtfully it needs a new coil pack.

I have since run through slick 50 fuel cleaner twice and have added slick 50 engine treatment to the oil. I have had the fuel filter replaced by my local garage and his thoughts were a sticky rocker. Since then I have MOTed the car at the same garage so the emmisions etc are all alright. I find it hard to believe the timing belt is out (though I think that the prev owner had this changed at the last service) as surely it would have much more severe effect if this is the case. Don't want waste money on a new coil pack on a whim - has anyone got any ideas?

Thanks in advance
Euan

 

[M. H. Greaves]

i have an 1800cc, and sometimes it happens to me, but it soon goes away and it all settles down. i know its a little worrying and disconcerting though. one time it was because i had put a few revs on it; i had my foot resting on the throttle inadvertantly, didnt even realise, any way then i switched it off. Because its an auto choke the next morning it was a bit rough, and my daughter waiting outside the lock up said she could smell petrol, it was flooded. Yes i know what the problem was; maybe its a fuel distribution/carburetion fault!? just a thought, it might spark the thought trains a bit.
regards, Mark.

 

[John Hollinshead]

.. Don't want waste money on a

new coil pack on a whim - has anyone got any ideas?

Likely as not is the coil within the injectors because I had all that done. Still no joy like a bag of potatoes on a cold start took it to a dealer, couldn't find a thing on the diagnostic. Next morning he tried it on a cold start, yep bag of *****. stripped the injectors found a damaged "coil". Replaced said part, works a treat

 

[Xan]

Thanks guys
I guess I have been putting the foot down quite a bit so Taking heed to Marks comments I was much more sedate in my driving and I have to admit the car wasn't idling like it has been. However John's suggestion seems very viable - maybe I miss understood when I thought he was talking about a new coil pack. So maybe it will be a trip to the dealers after all. Can you remember how much this cost you John to give me an idea what to expect. Thanks again Euan

 

[John Hollinshead]

much more severe effect if this is the case. Don't want waste money on a new coil pack on a whim - has anyone got any ideas?

I'll have to check back but I think it was around the £200. 00 mark but that does include the VAT. But do make sure that they test it COLD ie they've had it over night and HAVE to start it cold. If it's the price is any different I'll post again.

 

[Xan]

Well it has taken a long time to sort this one out but apparently the problem was the Oxygen Sensor and I have now had this replaced for about £200 and things seem to be much better. Not perfect but I think this is possibly the injectors are dirty/clogged as it has been running rich for so long. Euan