The smog inspection does not inspect or test the muffler. However if the muffler is severely damaged it may cause the smog technician problems with inserting and holding in place the exhaust emissions probe, and/or possible not allow the smog inspection to even begin.
If your Ford Ranger's muffler is intact but has holes you should know this... the BAR-97 smog machine is calibrated once every three days and is designed not to allow the testing of vehicles which emit high oxygen levels. If your Ranger has holes on the muffler large enough to vacuum oxygen from the atmosphere, the smog inspection may not proceed; the smog machine will not allow the smog test to continue. It will assume there is a fault with the smog machine's calibration.
