2001 Oldsmobile Alero problem with my Alero

I have a 2001 oldsmobile alero with 108000 miles on it. My car's with my uncle who is a mechanic and I had him check my car because I was told last month when I went to get an oil change that my intake manifold needed to be replaced. The mechanic from the shop wanted to charge me $600 just for the parts. That alone made me wonder. Few weeks later which was last week, my service vehicle soon light turned on. My uncle says the intake gasket is fine. He cleaned it up. I asked him to give my car a tune up as well. Is there a possibility that there was a problem with my intake or is it normal that there was oil on the gasket and just needed to be cleaned? Also my car tried to play "dead" and wouldn't turn on. I was told to put my key on "ON" for 20 mins which I did and my car turned on. I had a mechanic try to install an alarm to fix the problem and he says it wouldn't reset the security, and that's when I was told I needed to get a whole new ignition. Is that true? Could that be the problem why my car cranks sometime when I turn it on? By putting a new ignition will that solve my problem with the cranking?