I have done this to my lesabre and it made a huge difference! Yes, the MAF sensor can be cleaned. You MUST use electrical contact cleaner, anything else will damage it. The 3800 has a tendency of getting bad buildup of black gunk on the sensor and the electrical contact cleaner will make it run right off. just allow it to dry good enough before installation..
To clean your intake/throttle body...
1. remove the air intake hose from the TB.
2. Unplug and remove the MAF sensor (this IS a must)
3. (optional) remove the IAT sensor and spray the carb cleaner in here, and whipe out excess fluid.
4. Have an assistant start the engine while you hold the throttle partially open. (Engine WILL stall if you do not hold the throttle slightly)
5. spray the carb cleaner into the engine with it running. The engine will hiccup and act like it wants to stall. if it gets bad enough to the stalling point, stop straying and let the engine clear up. You will want to be consitantly revving the engine to around 2,500 RPM while you are spraying the carb cleaner in. after a few seconds of this you will start to see black smoke coming out of the exhaust.. this a good sign. you want this to happen. This is all the carbon being cleaned out. Make sure you spray the carb cleaner all around in the intake/ throttle body to make sure you hit all surfaces. The carb cleaner is also going to be cleaning your intake manifold as well/air passages. When I did this, it also cleared up a stuck open EGR valve.
6. keep spraying until you have used up all the carb cleaner.
7. put MAF sensor back on
8. put air intake duct back on
9 disconnect batttery (to reset computer)
10. hook everything else back up
11. start car and take for a test drive, it should idle much smoother, and run better in general
I also suggest using a bottle of SEA Foam in the gas tank,
You can also remove the VAC line goign to the brake booster, and pouring a bottle of the SEA FOAM down that with the engine running. Keep pouring until engine stalls.. pour in entire bottle and let the engine sit for about 15 minutes-half hour. Engine may be hard to start. after engine starts the VAC system will be thoroughly cleaned out, and black smoke will once again be pouring out of the exhaust.. again, this is a good sign.
when I did this to my LeSabre there was such a huge cloud of smoke coming out it wasn't even funny. the black smoke eventually faded to a dull gray in color. You know your engine is cleaned out totally when the smoke stops coming out. Hopefully this post helped you guys out some.
I know it sure helped out my car. Now I just need to do it to my riv.