Hello, I recently got a 2006 mazda 3 (150,000 miles) with the 2.0L engine, and I noticed that whenever I drive the car for about 15 minutes, it starts to idle very low like 400-500 RPMS at a stop light, and it goes back up when I pop it into neutral or park. When I turn on the AC is also goes back up, but occasionally idles low as well, It drives perfectly fine though. I already tried some things like changing the spark plugs, air filter is fairly new, cleaned the MAF sensor, partially cleaned the throttle body (might take it off to clean it better) and still no improvement! any suggestions on what else I should do? Strangely enough my wife has a 2007 Mazda 5 (220,000 miles) and I noticed that it does the same exact thing, so is it just a Mazda thing?
It can be a few things
A fueling issue
A vacuum leak
You have to do a idle relearn
Transmission issue
Unfortunately a lot of people have this exact issue and no can seem to figure out what causes it. They only thing that people say help is doing a idel relearn and resetting whole car by disconnecting battery.
