I have a 04 LLY i took the muffler off and replaced it with a flex pipe. I have E cheek around here it sucks but have to do it. Should i put my muffer back on when i take it to get it Echeeked or will it pass? Thanks alot.

forgive my ignorance, but what the hek is an E Cheek??? is that a smog test??

Muffler will not effect emissions. Pull the Kitty, you will fail the visual.