1997 Probe - Bogging down at acceleration after idle

Hello. I own a 1997 Ford Probe - standard model - 45,000 miles. I have replaced both O2 sensors in the last 2 years, the transmission 3 years ago and just recently plugs, wires, rotor & cap, and coil. Originally I had a check engine light that said I was too rich. Changed both O2s and then one day later, the engine light came on and said too lean. I was told it could be a vacuum leak. I did nothing and the light stays on. About one month ago I changed the exhaust flex pipe just before the catalytic converter. About one week ago I noticed the engine sputteriong and missing as I pull away from a stop light. Thats when I changed the plugs, wires, cap and coil. After that, still had the sputter and when I floor it from the light, it does not want to go to full acceleration. Its like something is holding it down. My wife says she can hear it sputter from the exhaust when I pull away from the house. I get good idle at around 500 RPM. Runs fine at around 1500 to 2000 RPMs too. Any thoughts.