When I started my car after a couple of days sitting it screeches when runing for about 10 seconds and then stops, never does it again the entire day, only on first startup????
Alternator belt- tighten it or replace it.
my guess is the air conditioning compressor. many people make the mistake of starting the engine with the AC on. when the belt gets at all loose, it will screech
warning!!!
be sure to loosen BOTH the front and rear air conditioning compressor mounting bolts BEFORE adjusting the tensioner, and then remember to re-tightnen them. failure to do that frequently results in breaking the compressor mounting ear, which then costs you a new $650 compressor and a freon charge.
The car will switch off the AC when starting.
I would also check the tension and condition of the belts.
only until the engine starts, and then it goes back on, which is when the screeching starts.