2005 Mazda 3 idles rough at stop light and sometimes dies

Do you have a check engine light on? Is the engine misfiring?

Sometimes that's caused by a vacuum leak near the manifold area.

Sometimes air in the coolant will cause an idle problem. Air will keep the air temp sensor from sending proper info.
Hope this helps.

2 things could be happening. One, the maf, or map sensore is bad. If there is a check engine light on, have it checked out. Second, it could be the throtle position sensor. Or just crappy gas. Rule the gas out first before changeing sensores.

The first thing to do is not set up the idle speed, but to set the Idle mixture screw to lean best idle setting. First, turn in the mixture screw until the engine dies or runs worse, then back out the screw (recommend turning ¼ to ½ turn at a time). The engine should pick up speed and begin to smooth out.

The battery has nothing to do with the idle speed

Spark plugs in your car are good for 100,000 miles. try changing fuel filter and add a can of B&G 44K fuel additive. This stuff is the best on the market and only available at dealerships. It conditions fuel pump and injectors, also absorbs water in fuel (methanol). Try this first, your car is too new for any other problems. this should help drivability and fuel mileage. If Nissan does not have B&G, I know Toyota does. Also stay with 91 octane fuel. Check oil and coolant often. do not risk overheating in traffic, watch your gauges......

did you gat some gas before it started running rough ? might be bad gas. were there any other codes ?

clean the throttle body most common cause of idle/decel die off. its cheap and real cheap and easy to do yourself

do you have a check engine light on? sounds like a bad TPS sensor.

Sounds like it could possibly be a vaccume problem, the computer sees that the vaccume has a low pressure and thus fludding the engine, or visa versa, it's seeing too high of a pressure and cutting the fuel comsumption to a minumum enough to make the engine sputter and die.. Does this happen when the cars in Netural or Reverse or Park? Just Drive?

The problem is a faulty solenoid in the vapor recovery system. The solenoid is sticking open and allowing fumes from expansion of fuel in the fuel tank to enter the air intake and smother the engine. This is how the Mazda service tech explained it to me. It is a known problem on the Mazda 3 in various trims which Mazda refuses to acknowledge. Usually the check engine light comes on and the engine diag code reads mass airflow sensor, which is incorrect. I dealt with this for 6 months on my wife's 2005 Mazda 3i before the dealership figured it out. My cousin bought a 2007 Mazda Speed 3 which developed the same problem after a few months and was cured by the same fix.