Re: v6 with no power
It doesn't sound like a problem with the MAF. In my experience, when they fail on V6's they won't run at all with it connected. Plus you say it doesn't run as well with it connected.
Have you tried a compression check to rule out a problem with cam timing?
I've finally fixed mine BTW. A blown coil pack had damaged the engine management computer. I've since replaced it and its back on form. Finally, after we replaced the lambda, MAF, plugs, coolant temp sender.... etc.
Try disconecting eac coil pack in turn with the engine running on the front bank, then if you find no problem with them, swap the coil packs and plugs front to rear and repeat.
If you can't find the misfire that wa the you could (use extream caution, if you don't know what you're doing then don't) test each cylinder for a spark individually by taking the coil pack and plug out, leave it connected and hold it in close proximity but not touching to an earthing point such as the cam cover.
DO NOT HOLD THE COIL PACK UNPROTECTED. USE INSULATED PLIERS!
This will allow you to check the strength of the spark. I found the problem with mine this way - the spark was weak on no1. Swapped the coil pack and plug with another piston and it was still weak.
So we checked the resistance of the wiring back to the engine management which showed no faults. Ergo, failed management.