I have a Fiat Brava SX80 1.2 16V (2000) which suffers a severe loss of power when attempting to reach 60mph on the motorway. Power drops off and the car coasts to a stop with the engine still running, albeit unevenly, before stalling. Switching the engine off and on again lets you continue on your way, but only for a short distance before the problem returns. The problem shows itself sometimes when driving through town at lower speeds too. No warning lights come up on the dash to warn of any problems. I have changed the plugs and leads and added injector cleaner into the fuel.