1999 ford explorer.. stalling, loss of power, cant accelerate?

I have a 1999 ford explorer, it started having what seemed like loss of power problems, then it started to get really bad so I took it to a mechanic who said, "sounds like your catylyt converers are blocked go get new ones... so $600 later 2 new cats.. i think im set and then I go to drive away and the problems still there.. I get a mechanic to inspect it they tell me.. your spark plugs and leads are absolutely rooted you need to replace them.. so being a ford explorer... $510 later were done.. I go to start the car still the same problem.. basically the problem is..

The car idles okay, but as soon as you you put it into drive (automatic) it starts shuddering and wanting to stall/shut off.. If I try to accelerate much its just shudders and dies.. if i put it in drive and. just slightly and i mean ever so slightly accelerate it will pick up speed slowly.. but no matter how fast it gets up to if I push my acelerator more than a few millimeters its just starts shuddering and wanting to shut off.. I had lube mobile run a computer reader and they didnt tell me much all they said is there may be a problem with your gearbox soleniods.. I dont have a clue and I dont understand how it could be gearbox as the gearbox never slipped or had anything wrong with it.. then all of a sudden this... also when i accelerate if i let my foot off and on.. it kind of makes a noise similar to a turbo.. Please if anyone has any ideas please help me out.

Bubb-L-Rap
July 2009