Gremlins at startup
I'm a newbie to the forum so please excuse any slip-ups. Have just re-entered the Alfa fold with a beautiful 1 year old silver 159 1.9 JTS. Awesome handling, stunning car but I have 1 major gremlin. Just after startup the engine sits at +- 1400rpm. It does so for almost a minute. During this time the idle is highly erratic. In some cases it is so bad there is clonking and banging from the engine bay (I think it is the engine rocking), with white smoke out the exaust. Dealer stated it was plugs which they replaced, but it is still doing it. The noise sounds almost like a cam belt slipping (rubber striking steel) which isn't possible as it's chain driven. The idle settles down after a minute to just over 1000rpm and all is well in the land again.
Has anyone had any similar experiences?