07 mcs automatic When rough idle occurs - car is in park -car is warmed up - engine code, manifold unmetered air flow The idle is smooth when car is in drive while stopped. I already had it smoke tested and replaced 2 hoses. I bought this car as a builder and put a new engine in it to make some money but it is kicking my *** now. The previous owner went 31000 miles without an oil change and drove the car till it blew up, the car was very under maintained for quite a while. I thought when I put new gas in it it would solve the problem, it helped because the car does not shut off anymore. I think the previous owner was running 87 and the gas did sit outside in the Wisconsin winter with a quarter tank for 1 month and inside for about 2 months so I know the gas was bad. Could and fouled out o2 sensor be causing this because as soon as the car gets warmed up in idle it starts choking up. I'm really thinking it is not an actual air leak but something that will trip the unmetered air flow code. I really wanna get this car outta my hair and sell it so I can pay off my 2011 mcs! Would love some advice thanks, Melissa

 

Vacuum leak, bad/dirty MAF

 

Thanks but I ended up figuring out that it was no real air leak just had to reprogram the ecu! So far idling good!