Hi,

I started a topic the other day about my 51 1.6 Focus juddering - this problem seems a lot better, if not gone all together now that I've changed the sparkplugs and HT leads/plugs.

I've been reading some other topics/posts and think the problem(s) may be linked or not what I first thought.

Firstly cilender 1 had a compression test done to it and the garage said it was low - making them think it's probably a piston.

When I changed the sparkplugs, 1 and 2 had a bit of oil in them - this has now gone with only VERY small amount in there (barely any).

So I'm guessing this has probably resolved the issue of the juddering - hence piston okay?

But the engine light is still on - also the speedo sometimes randomly drops to 0 - could be for a split second or for a mile or so.

Ford want £54 to plug in the machine and let me know the code - surely there's another cheaper way and/or finding out myself? :/

So, basically the thing is - is the light on for a 'faulty' piston or something else?

£54 is a good price its usually £70-90 sadly unless you have a code reader then no it will need plugged in you can buy cheap readers for £20 on ebay that can read codes and turn the mil off the speedo dropping is the vss sensor on the gearbox a pig to change especially if the pin breaks youre juddering may be down to that not plugs and leads

if the compression was actually low on one cylinder, then changing plugs and leads will not improve it.

remember from your other thread that garage didnt make a note of what the readings actually were, which is a shame,

low compression can cause a spark plug and lead to fail, so although changing them has improved matters, you could be curing the symptoms, but not the cause

think you might need to get compressions rechecked if only to eliminate it,

IDE say with the oil the piston rings are worn as above youre problem will come back the vss sensor really is the least of youre problems

think my car ran rough when the v v s was playing up!

Thanks so far - gonna book with Ford a diagnostic test and pressure test also.

Did the trip computer LEd thing.

Said E001 when scrolling through, then DTC was none.

Not sure if that E001 means anything at all?