The CEL won't always come on right away. Sometimes it will be immediately, sometimes in a few hours, days, weeks, etc. You will probably want to put the MIL's on anyways, so this way if the CEL does go on you will know it's most likely not due to the o/r pipe.
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-Aaron
"Lita"
97 Mustang GT Vert
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k&n, air silencer removed, Magnapack cat-back, BBK o/r h-pipe, Ford red front calipers
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