Hi guys, I am new here and I am hoping you guys might be able to help out. I just bought a 2010 honda civic exl automatic sedan and I dont know if this is normal but I'll try my best to explain. When the car drives from 0 to 25 mph the engine is nice smooth and quite, but when I start to reach 30 mph, I hear the engine kind of "thumping" or making a louder sound than normal, it just sounds loud, I mean its a V4 and I wouldn't spec an engine to make that sound. The thing is that after I reach 40 mph it goes back to smooth quiet sound, its just from 30 mph to 39, the engine just sounds louder, and even sounds like is slightly "thumping" not sure if that is the correct term, but I'm trying my best to explain. Please guys, let me know if this is normal for this car or if I should be concern. Thanks look forward to some replies! 
