Loose BOLTS!!!!!

Me and my dad were looking unjder the hood of my 91 sunbird 2.2L and cleand the terminals on the baterry and befor putong carb. back on i thought about checking the bolts on the crank case cause it looked like new oil was dripping out of engine and guess what, they were all loose so i had tightened them so that they wont keep coming loos i have to get torch specifications later. Could this cause the oil light and check engine light to come on? would this cause the engine to go into a low idle, and would it cause the engine to blow air out the breather tube on engine? could this cause any major problems?

any advice would d be appreciated.
Thanks, SS

i got the bolts- tightened to the right torch(excuse my spelling) the car runs alot better now. still can someone olz answer my questions.