Hello!
I own a Punto 60S (year 1994). For about 2 months I cannot reach speeds greater than 120 km/h. I have measured the TDC sensor and it has only 599 ohms (650-720 ohms in the car repair manual).Also the fuel pump is buzzing if you listen it carefully.

Should a buzzy fuel pump or the TDC sensor cause my power loss?

Thanks
Radu

The best thing to do is to take it to a Fiat dealers and ask them to either read the fault codes or run a diagnostic test to see if anything has failed. It could be the TDC sensor, Lambda sensor, MAP sensor, or fuel filter / air filter even.
Lambda sensors on Cinquecentos (very similar design) seem to have quite a short life.
Sorry it's a bit vague, but hope it is of some help.

Pete.
Cinq sporting
http://mysite.freeserve.com/close_to_cracking_up/

change your fuel filter first its the cheapest and well worth a try