I have a 1998 Mercury Mountaineer 5.0 V8. The other day, after driving around town running errands, I randomly lost acceleration power almost entirely. It starts up and runs, but with the pedal to the floor I go from 0-30 in about 30 seconds. It chugs really badly to even get me up to that speed, and I'll top out at about 40 before it starts chugging and sputtering and sometimes sounding like it's backfiring. After running a check engine scan, I've replaced both the throttle and camshaft position sensors, with no improvement whatsoever. I had numerous O2 sensor codes, but I've been ignoring/unplugging those since the first one popped up. I normally had loud exhaust due to that, but it sounded like a monster truck and didn't affect much anyways so I was cool with it, now it sounds more like a big tractor chugging along. I have also had it stall and quit on me a few times in the past couple of days. I'm getting roughly a whopping 5 MPG according to my calculations so far... HELP ME!