backfire

hi guys got to reading some of the threads and found some good things out about my truck thats why i joined up,go by freightshakerblues been driving for 35years & love it all. my truck is backfiring& black smoke puffs every time it does this,got good power and its good when im in top gear it only does this on takeoff as im going up gear.is there anyone out there that knows any thing on this? iv been home 7days trying to get this fixed,but all i get is maybe egr or turbo.i dont want to spen $ idont have if its not those things