fiesta 1.25 zetec running problems - fwluffy
Can anyone suggest a reason for the following??

I have a 1997 Ford Fiesta 1.25LX with a zetec-s engine. Its done about 55000 miles.

Occaisionally the engine seems to bog down and suffer poor acceleration for up to about 30 seconds and then suddenly surge and pick up speed even when keeping the same throttle position.

It happens at all engine speeds in all gears and it doesn't seem to matter whether the engine is hot or cold.
Apart from that it runs fine and.

I'd appreciate any suggestions for the cause of this.
fiesta 1.25 zetec running problems - Kingpin
I would check the ignition system, sounds like it could be a coil or ignition lead fault creating a mis-fire when the engine is under load. I had a similar problem once and the main dealer diagnosed a faulty high tension lead.
Best to get this checked out soon as the poor running could damage the catalyst.