today i was sitting at stop and my all of sudden sputtered. I thought hmm that was weird , the it did it again. About 30secs later again. I was like WTF is happening. I checked to see if gas a little less than half a tank.Checked to see if there was an error code but nothing. Anyone have an idea what it could be (bad gas,spark plugs)? It an 05 gt with 16,500 miles.Any help would be great.