My 2003 Impala has been running fine for months now, after about 6 months or more it got exhaust work and 2 months ago it had to get exhaust work again.
The muffler actually fell off on a long drive and a garage nearby said the previous garage totally screwed it up because the said the exhaust pipe was cut too short and they had to weld together a “fixer piece”.
Then we took it to our local Firestone simply to get the hubcap covers taken off as it was a free service and after we had to them put back on, about 1 day later, we started getting a strange noise.
Everything sounds fine when you are idling yet the minute you start moving and especially with all the windows up it sounds like somebody is running a lawn mover or an airplane is flying above.
There is no vibration or anything just that strange noise.