Mk4 Fiesta Hesitation under Acceleration

[Martin]

Hi all, we have a Mk4 Fiesta 1.25 zetec engine (automatic). It started out as a small hesitation ages ago which we lived with. Recently though this has become really bad to the point where we have had to take the car off the road due to it being dangerous having quite a few near misses.

It seems to happen when the throttle is fully open, and the engine seems to go into some sort of limp mode - the revs die, there is zero acceleration, and the engine is in tick over - it never stalls though. Take your foot off the throttle and back on it seems to clear and you are on your way. It doesn't happen every time, for example last week I drove it for a good 45 minutes around town and it did it once after about half an hour.

My dad has tested the throttle position sensor which he says goes open circuit at full throtle, does anybody think this is the cause, or does anybody have any other ideas before I spend 30 or 40 quid on a new sensor.

[Steve]

hi

does the engine light come on at all?

[Martin]

Nope, no warning lights at all.

[Steve]

shame.. otherwise could have checked the ECU for codes.

[sonnywillats]

hello there i have exactly the same problem, only its on my mk 3 fiesta, please get back to me as to wether you got the problem fixed. i have tried so many things