Problems with valves!!! Need Help!!

I was racin the other day and something happin to my motor..I kept on have to keep idlin up cause my would shut off if i didnt.. my motor was shakin and i didnt know what to do..i turned on my car the next mornng an the idle was fine but when i started it it sounded like shit..I had put in DC headers that same day and an Aem cai the day before..would that have anything to do with it? someone told me i might have to adjust my valves..any suggestions??