1998 Renault Scenic DTi Queries

[ScenicDTi]

Hi hopefully two quick queries have a 98 Version with the f9Q DTi engine.
First problem fuel and temperature gauge fluctuating about 5 mil on occasions annoying as not all the time have reconnected multi plug on back of dash problem still there.
Also after starting drive about half a mile or so then engine hesitates as if air in system after a couple of coughs ok for rest of journey only bad after a while of parking more than two hours, had all fuel lines replaced does anyone know how to overcome this problem
Thanks Iain