I have a 1990 buick lasaber,3.8 liter, it is overheating,thermostat good,rad is hot on top but cool below, remover rad ran water through bottom of rad does not seem blocked,i am not loosing coolant,no coolant in oil,no white smoke, so headgasket seem fine,car is idling high,dont know y,cannot get gas/air mix correct,could this be cause of overheating?. So can someone please give me an idea,have check with several mechanics,but cannot give me a definat answer,HELPPPPP :shock: