The 2.7 doesn't have an idle air control valve, the e-gas system controls throttle position to maintain idle.
Also, typically, if your MAF were bad, you'd notice it while the car is running under a steady load, not just at idle. You could try disconnecting the cable harness to the MAF to see if the car runs better, but I doubt that's your problem.
How many miles are on this car? You might just need to clean out your throttle body if there are no vacuum leaks.