Fiat Punto high pitched engine noise (choke?)

[Daniel]

I've a 97 (p reg) Punto 55 (1.1 l) and it's been through a major service at 58k miles.

But on the road, when the engine's just off cold, but not yet warmed up, after about a mile, the engine emits an odd high pitched humm that goes up in pitch with the revs on the car.

It's been doing it for a while (year), kicking in at about 2.500, and going upto 3000 rpm before it kicks off, then changing gear the rpm drops back into that range and this noise starts again.

Then after the engine's warm it fades off and stops. One mechanic suggested it was the valve system that Fiat use for the automatic choke system that was to blame?

Lately it's been getting worse. Drops off at 3000 rpm, then kicks back in from 3.5 - 4 thousand rpm.

Idea's as to what the problem is?
Does it need attention?
Is it costly to sort out?

thanks.
Daniel.

[friz]

I know it's a late reply but....

I had this same problem. '98 Punto, 75K miles. Turns out it was the timing belt tensioner. Got new timing belt and bearings put in yesterday for around €120 at a main Fiat dearler.

Had a major service back in Oct 2002 just before it's NCT and they told me then that the belt needed changing at 75,000 miles. They were off by about 250 miles. If I was cynical I would say they were designed.....but I won't.