I have 2008 Nissan altima. Last month the engine would sputter and then stall while in the idl . The rpms would drop to 500 and die. I took it to 3 shops. Finaly I broke down n took it to a Nissan shop . they found a lady bug caught in the MAF

. Now after all of that the car is starting to do it again

. Only it will drop to 500-600 rpm and idle there without stalling and no SES light is on. The car doesn't shake or vibrate at all. I went and cleaned out the MAF and throtle body i put some seafoam intoit around the same time i was having the issue above, but that did nothing to solve it. Should I try replacing the MAF or taking it back to the shop and seeing what it could be. After a lot of research I am now convinced it could be anything from a computer issue to intake manifold control valve to the mass air flow sensor again. Any feed back would be helpful. Thank you.