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Our tanks ARE made of plastic, but sediment isn't just rust, all sorts of debris can get into your tank when refuelling... Like what? And don't forget there's a fuel filter to take care of it anyway, running a tank to near empty just issn't the problem it used to be, cars used to have steel tanks and no fuel filter, I remember regularly cleaning rust residue from the float chambers of an old Triumph.......

Tank sediment is much less of a problem with newer cars, mainly becuase they are new and the inside of the tank hasn't yet gone rusty and also becuase the tanks are generally now made of plastic and don't rust anyway! Mine averages 54MPG, it went down to 47 recently but that was down to a faulty spark plug.

Hi, I am a long term pertrolhead and I know what clutch slip is and feels like, as I said before this was hestitation which is generally caused by lack of fuel, lack of air (less likely as this would lead to lack of power) or ignition problems..... The new plugs have CURED the problem, I was just pointing out that the web site mentioned says that this "corona stain" on it's own does not indicate a problem with the plug, however, in my case replacing the plugs HAS cured the problem so it's either associated with this stain or it's an invisible problem within the plug which in all honesty has been the case I have seen for other plug issues, you know it's faulty but you can't see that there is anything wrong with it. If it was clutch slip it would not get any better, it would only get worse! Cheers, Darren.

OK, so I did a search and according to this web site: http://www.sparkplugs.com/sparkplug411.asp...tain&mfid=0 this is not a problem: A used spark plug sometimes has discoloration around the insulator surface which looks like gases that have leaked between the insulator and the shell. This discoloration is generally called "Corona stain" and is caused by charged oil particles in the air around the insulator surface that are attracted by the corona discharge and then adhere to the insulator's surface. The corona stain does not at all affect the plugs function or performance. So the plug I showed may not be faulty, but replacing them HAS cured the hesitation problem.......

Changed the plugs last night and all is restored to normal, was much easier than going back to the stealer, set of NGK plugs off eBay (£11) and all is good. Here's a picture of the offending plug, looks like the insulator is breaking down (apologies for the poor quality, it was taken with my iPhone):

I know, it's just the inconvenience, if a set of plugs doesn't cure it Illl get them to have a look

Hi, Thanks for the reply, its on all gradients, I too thought spark plugs, Ill get a set and try thrm. Thanks, Darren.

Hi, I have done a quick search but cannnot find any threads on hesitation issues with a petrol Aygo. My car is a 2008 model and has done 18K miles, just recently I have started to notice hesitation when accelerating hard in 3rd and 4th gears (might be present in 1st and 2nd but not as noticeable). If I am driving along a dual carriageway and looking to overtake someone I might change down to third and accelerate hard, from about 50mph the car hesitates/surges as if there is a lack of fuel or spark plug is breaking down, back off the throttle and all is well again...... No issues with tickover or acceleration in 1st and 2nd.... Any ideas? Thanks, Darren.