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Over the last couple of months I've noticed that its becoming harder and harder to drive smoothly at low speeds or on light throttle. At first it was almost like a slow rythmic judder but over the last few days its become a fair bit more noticable. The car runs ok otherwise, sounds ok and has been regulary serviced and had the belts done last year. Its most noticable in crawling traffic, 1st and 2nd gear but I can feel a slight judder even when in quicker moving traffic on light throttle.

Anyone got any ideas what I should be looking at? I reckoned its something to do with the throttle cable sticking but I believe most modern cars have all kinds of electrical nonsense related to the throttle too.
 

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Probably a failing/slow lambda, or possibly a misfire due to a pluglead or coil, or a leak in the air intake system.
 
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I hadn't really considered the leads or coils as I thought they'd just lead to generally rough running. I'd had a look and the air intake and it seems fine, no obvious signs of leaks or hissing.
 

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My 156 also has this problem nivens. Will be interested to see what the cause is. Cleaned maf but no difference.
Next was changing the plugs and leads as new car to me and needs these service items replaced anyway.
Don't think they are the cause though as would be shown at revs also. Above 3k the car is sweet.
My thought process was maf not reading low airflow properly.
 

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A weak spark in cylinder(s) can definitely cause jerky city driving but not be noticeable at higher revs. I changed lots of parts before finally sorting out this issue with new plug leads. The symptoms were that the car did not slow smoothly when I took my foot of the accelerator, but seemed to keep going for a fraction of a second and then slow down suddenly with a bit of a jerk. Made city driving nearly impossible.

Could be MAF alright but these more often show up problems at higher revs when failing.

I still go for lambda, especially if the car is not driving smoothly with constant acceleration. Lambda switching can become slow and you can then actually feel the ECU leaning and richening the mix as you drive, causing the car to jerk along when crawling in traffic.
 

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Cheers mo4, will replace plugs and leads and see how she goes. I have also reset the throttle but haven't yet taken it for a spin to see if it worked.
 
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