Rattle noise on accel.

I have a 1994 Taurus GL, with a 3.8, and HIGH mileage (130k+)
I got the car just over 3 months ago, and everything was running great. However, recently the car has started making noises, barely noticeable at first, but now, It is audible even above the stereo. It seems this noise (deep rattle) is only on acceleration, and gets worse the harder I push the pedal. Also, the car seems to have lost all fuel economy, and I'm currently getting about 10-12MPG(dunno for sure if these problems are related)
ANY suggestions would be appreciated, as I need RELIABLE transportation.



P.S. Please help a dumb-newb!

I noticed a handful of people viewed (18?) this post, but nobody replied...is the car THAT messed up?!?!?

PLEASE HELP!
This thing sounds like it's gonna fall apart, and the mechanics around here seem completely clueless in relation to this problem. I was hoping to get AT LEAST a couple years outta the car, but at this rate it wont last another week!
Please don't hesitate if you have any suggestions.

The car is going to the mechanic on Saturday the 20th, because the rattling turned to a clunking (as if something has broken loose in one of the cylinders). Please help, cuz, frankly, I'm not sure whether to trust the mechanic or not