2004 Toyota Camry Engine cold start problem

Hi 2carpros,

i experienced an engine cold start problem with my camry early in the morning or after parking the car for more than an hour. The engine would rev up to 2000rpm n drop down to 1000rpm then up and down again upon start up, then the car would start to vibrate as if it is experiencing a mis-fire. And the Battery light comes on for about 1min before going off when the engine rpm stabilised.

i had recently sent my car for bonnet replacement and the problem arises after the bonnet change. i had changed my car battery 2 mths ago
What is the likely cause of this problem, pls advice

Thanks

Danny