In terms of cleaning the MAF sensor, the 3.4L is a speed density engine:
Speed density cars use a programmed set of variables to deliver the fuel requirements of the car. It reads things like engnine temp, throttle position, 02 sensor, etc and delivers a set fuel curve. However, it cannot determine what mods have been done to the engine. Install a cam, which allows more air to enter the engine, and the computer cannot compensate. This usually leads to problems.
What this means is that the MAF doesn't exist on a 3.4L V6 - the computer wouldn't know what to do with it if it was installed anyway.
What you need to do (this is a must for anyone trying to troubleshoot any 1993 or later vehicle) is get your car scanned somewhere or buy a scanner and do it yourself. The reason for this is twofold:
1) The scan will give you codes that will help you track down the issue.
2) The 3.4L has a speed governor. If you hit 108mph, the pcm will limit the fuel relay and could lead to engine shut off (I've experienced this in my car). It's entirely possible you have a E/PCM problem and the code scan would reveal this.
You really need to have the E/PCM scanned to see if any error codes have been thrown before trying to go any further on this problem.