skoda octavia 1.6 estate petrol 2003 model - engine running rough/poss misfire, shuddering

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Tue 12 Jun 2012 12:34
skoda octavia 1.6 estate petrol 2003 model - engine running rough/poss misfire, shuddering - madamf

Now i've found a cure for the engine management,thanks to craig,my car has now developed over 3 days a gradually getting worse enging problem.

The car ticks over and runs very roughly,like its missfiring,struggeld to get up a hill and now can't drive smoothly above 2nd gear or the car shakes badly and then stalls..

some grey smoke and a slight smell of burning..

can anyone help with a diagnosis?

best wishes

MAdamF

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Wed 13 Jun 2012 11:09
skoda octavia 1.6 estate petrol 2003 model - engine running rough/poss misfire, shuddering - craig-pd130

Has the coolant temp sensor been replaced yet? If not, it's probably overfuelling and running too rich.

If the engine management module thinks the coolant temp is minus 15C, it will instruct the injection system to fuel accordingly, which is no good when the car's actually at operating temperature.

When the coolant temp sensor died on my Dad's Octy, it didn't throw a fault code. I got a tip off from here telling me what to look for (from the much-missed Screwloose poster), then the garage plugged their diagnostic tool in and saw the coolant temp spiking from freezing to 80+C in half a second.

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Wed 13 Jun 2012 19:23
skoda octavia 1.6 estate petrol 2003 model - engine running rough/poss misfire, shuddering - madamf

Hi Craig,

Thanks for this. since then i have taken the car to my local trusted garage and they have tried the coolant temp gauge and say it isn't that but they say its soemthing called a stepsensor which apparently is not cheap,so for now i'll just have to put up withe car hunting up and down when it gets hot!

on the rough running they found it needed new HT leads and that has done the trick and is back to normal (almost!)

anyone else had a problem,and big thanks again to craig.

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Wed 13 Jun 2012 20:31
skoda octavia 1.6 estate petrol 2003 model - engine running rough/poss misfire, shuddering - craig-pd130

Be very wary about them replacing the "step sensor", those motorised throttle bodies are £200 for the part alone and you have to buy the whole part. I would seriously advise changing the coolant temp sensor first, and if that doesn't solve the hunting, THEN you can replace the throttle body ....

As mentioned, the coolant temp sensor does not throw a fault code! Swapping or monitoring its output is the only way to detect a failing unit ...

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Fri 15 Jun 2012 00:51
skoda octavia 1.6 estate petrol 2003 model - engine running rough/poss misfire, shuddering - Big John

If replacing the HT leads has "almost" fixed the rough running then I would suggest the coil pack. When failing then new leads (old ones leak a bit) seem to help but not fix the problem.

When you have leads on this engine then you have a wasted spark coil pack (one coil per two cylinders). - change this next whatever the diagnostics say (can show wierd results). Don't drive too far without doing this otherwise you may damage the catalyst as it can be damaged by unburnt fuel.

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