I just got my 97 c1500 truck back from the shop. I got the 350 redone to a 383. I just put around 500 or so miles on it and it ran smooth. The other day I got in it went for a lil ride to my dads house and before I got there the thing started running like crap. It is showing 0300 code. Changed the cap,rotor, map sencor still no change. Not sure what it is. Need help. The engine is still breaking in.