Over reving 1240 16v fiesta

[ETY]

Hi all my 1997 fiesta has developed problems ! some times it revs up without any throttle pedal pressure and also refuses to rev over 4000rpm when under load it feels like its hit a rev limiter , but when stationary it will rev through the range problem free , any suggestions would be most helpful many thanks

[M-Ster]

sounds like idle cotrol valve common on these try cleaning it really well with carb cleaner before buying a new one worst case if it doesn't work you have only lost a fiver

[roscozs]

Vacuum fault perhaps. I know there's a vacuum pipe onto the inlet manifold that can slit causing the symptoms you've suggested.