i replaced my alternoter now my truck will not pick up speed i have tried all on 2002 GMC Yukon XL Denali

i have tried all arears even took my neg. turnmnal off to reset it

by in Rockville, MD on January 25, 2013
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1 answer
ANSWER by , January 25, 2013
scan for codes or ck for plugged exh system. did you have this prob b4 you worked on it?