My check engine light turns on and off multiple times throughout the week. I've used the code reader at schucks but it reads no codes? even when the light is on. it has a slight hesitation, and at cruising speed it kinda surges. Any ideas??

 

try using a paperclip instead and jump a and b terminals.

 

and then i would count how many times the light flashes if at all?

 

Should flash once ,then pause ,then flas two times. That is normal, that is code12. Also your secondary fan should come on.