Ford: 1999 Ford Escort, o2 sensors, service engine soon light

Question
I have a 1999 Ford Escort SE 4 door.  Recently the Service Engine soon light started blinking on and off but would not stay on solid.  Once you got going around second gear it would go off and sometimes not come back for days or weeks.  Now the car is losing power.  When I step on the gas is the car sounds like a lawn mower (like an exhaust leak, but none exist that I can see or feel) and has no power at all.  Once it finally gets to about 30 MPH it clears up and is fine.  What could be causing these problems and are they related?

Answer
Rob  what i want you to do is go to your nearest auto zone they will ck your comp for free let me know what codes they come up with. Now what i want you to do is remove the o2 sensors and drive the car and see if your power comes back. if it does then your converter is clog and needs replaceing