Won't rev on start up

You need it code read,better than half the time on these the "fault codes" turn out to be short circuits to earth or power.
Most common I've found are under the air filter box pressing the injector wires but I've found them on the CAS wires,the AFM wires and also other places.also prone to the vacuum lines (small 6mm pipe) that run to the turbo pressure sensor etc filling up with crud,blow them clear.
You can get very deep into these without quality readings cash payed up at the start can save a lot long run.

Hi thanks for the reply do you no if a op com would be able to read what the problem is? Not having no joy at the moment. Does any 1 no any garages that would no how to help me in the south Yorkshire area? Thanks

Should do,problem is when it comes up with a code for say the afm and injector #3,doesn't mean these are faulty,could mean wire short on those lines.
OpCom it and record the codes,then you can get somewhere,don't replace anything because the code refers to that item.
But be warned!I've striped off the entire harness on one of these before and went over every wire at the bench,I gave up counting the shorts after 10,Renault protocall was any more than 4-5 faults and you renewed the harness.and it is a Renault after all.
Good luck.

My Vivaro would run for a few weeks perfectly, then it would play up, it would take 10 seconds for the throttle to work, run very roughly until 3k revs then would take off like a scalded cat.

Finally I realized that the van suffered very badly from water (Rain and windscreen washer) getting under the bonnet and wetting the engine.

I believe this is the biggest cause of faults under the bonnet

Check your turbo boost sensor, Its the "windscreen washer" looking unit with 2 rubber pipes coming of it, If the pipes come from the top it is upside down, and water is in the filter of the boost sensor, Mine was fitted this way by a garage, and I have fitted 3 new ones,
Water drips directly on to the top of it, water does get into the unit
The cap on the unit unscrews, inside there is a foam filter, 10 to 1 it is wet, (I have squeezed a teaspoon ow water from mine)

But to stop any further problems you MUST SEAL THE ENGINE COMPARTMENT

I sealed mine this weekend, a fairly long but inexpensive job and even after the very heavy rain this weekend there is no water on my engine, and my van runs, at 80,000 miles as well as the day I bought it (at 5000 miles)

I will cover the seal procedure soon,