This happened twice to me on my way home from work.

It's only a 15 minute journey, but was annoying because of the traffic behind me. Both times I was in 3rd gear, at around 20mph, the first time slowing down, the second time speeding up. It wasn't as if it was low revs and it stalled, it just very nicely and smoothly cut out, and the car would just roll, then i had to stop and it would take 2 or 3 minutes before it would let me start it up again.

Car is a 1.3 Felicia Classic, 2000 X reg.

The sparkplugs are getting changed this weekend, with a full service (been meaning to do this for 3 weeks ), so what may be the cause?

Other than that I have to get a new exhaust (from behind the cat to the back) as mines is busted thanks to some speedbumps with loose bricks, been quoted

i expect the coipack is overheating.

is yours a single point or multipoint injection?

Either that or the crank sensor is playing up.r

i expect the coipack is overheating.

is yours a single point or multipoint injection?

2000 "X" should be MPI.

Yes, it is an MPI

are either of these expensive or difficult repairs?

A crank sensor is about £30 iirc and very easy to change, just sits in the top of the bell housing of the gearbox.

it would take 2 or 3 minutes before it would let me start it up again.

This could be indicative of a faulty coolant temperature sensor. If you do end up having to replace this check your thermostat first, as if it is faulty it will be more economical to replace the entire thermosat housing as it comes with a temperature sensor.

you can download a .pdf of parts prices from here:

http://www.jhmbuttco.com/

some parts are "pattern", some OEM.

Don't forget the postage cost on smaller items does mess with the economics, as does his returns policy if you order the wrong part.

Also, consider specialists/factors for things like alternators - I got a proper brand new "magneton" 90 Amp alternator locally for 120UKP, which is about half the Skoda price, and less than JHMB even before postage.