Its started holding back when cold and massive oil leak from cam cover.
As said the holding back when cold is most likely going to be the inbuilt inhibitor in the ecu to limit the revs when cold, it should only do it for a minute or so, if you let your engine warm up for a few mins before setting off, it probably won't do it.
The oil leak is most likely from the cam cover, quite a few people on here have had their cam covers re-sealed under warranty, but your warranty is up by now i would think.
A dealer quick fix was to remove the cam cover bolts one at a time and put loctite under the bolt head/flange to seal it to the cam cover, as oil was coming up the bolt hole and covering the top of the cam cover, but it also leaks between the joint of the cam cover and head just above the inlet/exhaust ports at the front of the engine.