90 deville still cant find the problem

Okay im still trying to figure out why my 90 deville wont run. I ve done a total tune up on this car had tps tested, Rechecked all plugs and wires checked fuel pressure and vaccum which is good. As i was taking out plugs on the backside of my engine i noticed that the o2 sensor between the motor and the cat was broken off and just hanging from the wires. I know this needs to be replaced but is this why my car doesnt want to run worth a ****? I was on my way home from kansas city, a 3 hour drive when i just suddenly lost power. My fuel economy (http://www.automotiveforums.com/vbulletin/#) went from 16 miles to the gallon on the highway to around 4, Yeah 4 and i could not get my car to go over about 40 mph no matter how far i pushed the accelerator. Only code i am getting is idle control motor which ive replaced. I cant seem to figure out why i am not getting a code for the 02 sensor being broke in half, is my ecu going bad? I heard something about blowing ecu chip from driving without o2 sensor is this true?? Someone please give me a hand here I need my lac back!!!!!!!!! I just bought it! Plus in the mean time im stuck driving my girls 95 FORD pos taurus. Someone help please!!! Thanks

Without the 02 signal, it might never go into closed loop. Use a gage and check fuel pressure, see if the pressure is correct and see if it holds, when key is turned off.

Hmm previous recommendations still not done, how is the vacuum when at part throttle does it drop way back, still need to test cat and recheck the fuel pressure, also look for fuel in the hose at the pressure regulator at the rail. To loose power like you descibe only a severe miss, blocked cat or low fuel pressure can cause this. BTW, both injectors in the TB are working, correct?

Yeah my fuel pressure holds steady at 40 with the key off pressure regulator is not bad. Vaccume is good. Im about to go buy a o2 sensor and unbolt the cat in a little bit see if thats it. I think thats about the only thing left to check so ill let you guys know what going on thanks for the help its Greatly appreciated, thanks