The smog test does not test the muffler. However we don't recommend you take your Ford in for testing without it. It may cause the smog technician a
problem with the emissions probe. Smog machines calibrated in California
(which they all are, every three days) are designed to not allow the testing
of vehicles which emit oxygen levels exceeding a smog machines preset
limits. In other words, if the technician can not get the emission probe placed properly into your Ford's exhaust stream, enough oxygen could enter the probe to not allow the inspection to continue.
posted by SmogTips Support
