Chevrolet: 1994 Camaro, factory tires, dirty fuel

Question
I have 94 LT1 my check engine light comes on,,, but it comes on and off and when it comes on i notice my far are running extra loud and when the service engine light goes off i dont hear the fans anymore what could be causing that?

second issue is we but 21" rims on the car and after a while i notice when i take off from a stand still the car heasitate, it acts like someome 1000  pounds jumped on the back bumper as i went to take take off then it stops and the car goes about its busines we put the factory tires back on it gives the car more speed but it still does it, what could this be?  

Answer
whenever you have a check engine light the fans will come on.

You should get the car scanned. I'm sure the light will tell you why the cr is hesitating off idle. Its not your wheels.

Try resetting your IAC: http://shbox.com/1/4th_gen_tech2.html#iac_reset

Otherwise it could be dirty fuel injectors or a clogged fuel filter.