Two problems related to loud engine noise have been reported for the 2006 Mazda MAZDA3. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Mazda MAZDA3 based on all problems reported for the 2006 MAZDA3.
I was driving along and suddenly a loud noise, the check engine light came on and the car shifted from 4th to 3rd without losing speed (except from me taking my foot off of the gas when hearing the noise) all at the same time. My mechanic said the diagnostic machine pointed to the "turbine speed sensor", so this was replaced within 2 days. The same day I got the car back, I drove it about 30 miles and it did the same thing again. Now my mechanic is checking into the transmission, possibly causing the problem.
Rubbing sound coming from front passenger wheel when turning hard right, as well as wheel hop. Diagnosed as a broken engine mount which led to a broken strut. Both had to be replaced. Mazda refuses to fix, despite numerous reports of bad engine mounts.