still drives like i have a chip and its off!!??!

[White7.3stroker]

last week my truck quit running and my mechanic said he thought it was the computer so he put a new one in and the truck still cut off on me today but crunk back up then missed a little bit later while i was going threw a parking lot and the truck runs and smokes like it has a chip but i havent got it reburned after the new computer..do u think the chip might have made my truck not run before i put the new computer in it and if so could i get it reflashed would it fix my problem???