Kia Cerato

Acceleration causes and how to fix it?

When the overdrive is on the engine will rev up like its about to take off but there is no power at all, in fact it seems to slow down and you have to lift your foot off the accelerator to regain any power

Engine turns over but will not start,occasionally catches for a few seconds then fails.Two hours later or next day it starts fine. Acts like there is no petrol. Garage has first cleaned then replaced sensor in fuel tank, but no joy. The car...