new muffler causing missing?

[djpj]

i put a aftermarket stright through muffler on my 90 laser. now it seems to miss bad when start from a stop or ideling? is there somthing i need to do to fix this?

 

[GSGoinFast]

i put a aftermarket stright through muffler on my 90 laser. now it seems to miss bad when start from a stop or ideling? is there somthing i need to do to fix this?

by missing do you mean misfiring? if so, id check your plugs and wires first, usually the culprate.