my engine loses 2-300 rpm when kicked in to passing gear. on 2003 Chevrolet Silverado 2500 HD

I have replaced the rubber fuel lines. the check engine light came on but went off before I could read the codes.

by in Rhome, TX on September 04, 2013
2 answers
ANSWER by , September 04, 2013
Codes are still there, unless you have removed the battery cables for some reason. Computer has a good memory! Turbo working?
ANSWER by , September 05, 2013
scan codes and post so we can adv