Could be crankshaft position sensor. That would affect starting from cold too. If it's the C.P.S. it's only one bolt to change it.
Does it misfire at all? Could be coil.
Could be airlock in petrol tank, causing fuel starvation after a few miles.
Don't know about the 2nd gear bit - maybe coincidence, maybe not.
It's out of warranty so why not get a good independent Renault specialist to look at it.
Chicks Fan
December 2008