1994 Ford Probe slow accelaration

I bought my probe 3 days ago and it ran like snale in an olympic event. Ive down all the major tune ups ( spark plugs, sparkplug wires, oil change, air filter, cleaning MAF, ect) and when I push more then 20% on the throtle it still boggs down, i'm thinking it may be due to my o2 sensor (due to internet reading) but not sure, my check engine light comes on during mantaind rpms or at high speeds. Before replacing the o2 sensor or bringing it into a high price shop id like to get some feed back. Please let me know what you think, from what ive read this is a very reliable source. Thank you