I have just bought a Skoda Fabia 1.4 W reg and have had problems with it since i bought it, from what i can work out when i start it sometimes it will take a while to start, if this happens the performance is very poor as regards to acceleration BUT, it would not break down on my journey. But sometimes it will start straight away, although the performance is drastically improved, it meant that at some point in my journey the car would break down. What would happen is when driving along steadily with the revs in between 1000 and 2000 it would jault and then keep jaulting and slowly lose power. To correct this i would switch my engine on and off again and sit in neutral watching the rev counter going up and down rapidly on its own without me touching the gas pedal. if i put the pedal to the floor to get maximum revs in neutral the rev counter would go up and down rapidly until eventually stalling, then i would switch my engine off and try start it again which would take a while but would work jus with very poor performance again. As an inexperienced mechanic i have no idea what this could be and need some advice on how to deal with the fault?? Also on my way to work it had one final breakdown and now when i start it up its like sitting in a washing machine it violently judders and vibrates and when applying the revs the rev counter jus goes up and down staying just above 1000 rpm so i am now off the road, please help. :rotz:

Sounds very much like an intermittently failing coolant sensor.

Failed on my Y plate 1.4 (16v petrol).. thing would be fine one day and refuse to start the next, it'd turn over and over and eventually groan into life very slowly with a ton of smoke. Other times it's start and then idle at 2000rpm (it did this to me one time leaving a petrol station and I nearly lost control as when I put my foot down, rather then going from 1000 - 2000rpm it went from 2000 to 3000rpm and I launched forward.)

Was always mostly OK once driving.. so sounds like the same thing, it;s the sensor telling the car all kinds of temperatures so it adjusts fuel according to it and ends up over and under fuelling.

Also sounds like your throttle body may need a clean. If it's a 1.4 16v then the revs are known for being just a tiny bit unstable.. but nothing to effect driving.. normally just when idling. Lots of info on that issue.. use the search

I'm not sure, but two other possible causes are a faulty accelerator pedal, but this is unlikely.. or a faulty cam position sensor? I don;t know much about either of these faults though. but they have come up before so (sorry to say this again) a search would prob bring them up. The coolant temp sensor is the best place to start I'd say though.

Edited 9 June, 200917 yr by reflex88

I'd go for a possible throttle body clean and align, but you really should get the car hooked up to VAG-COM first to get the codes read, and do some basic checks like HT leads and plugs.