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I replaced my O2 sensors over the weekend because I had really low fuel economy and I heard that this had helped a few others. Well, now my check engine light is coming on. It comes and goes about 2-5 min intervals. I am sure its the O2 sensors. Do I need to reset the computer? Do they need break-in time? My car seems to be running normal, but I havent had them in long enough to see if the fuel economy had changed?
Should I take them back to Autozone ASAP?
Just to clarify, the check engine light neevr came on before changing the O2 sensors.
Same thing happened to me. no light before O2's and i hooked up the 30 acron computer scanner for 95 and older fords and it told my which one wasnt reading good.
I got under the car and cleaned the connector on the O2 and the connector that goes to the O2.
Only other thing is that you have the wrong O2's. just go online and check the number on the box with the one online and that should tell you if you got the right once.
ALSO,
Clean your MAF and change your fuel filter and once your low on gas get a complete fuel system cleaner from GUM and fill up with gas.
The only other thing would be use seafoam on your car an hour before your next oil change and make sure your Spark plugs are good and gapped properly. Make sure your distributer cap and rotor are still in good condition if not go to advance auto and get a MSD cap and rotor set. Make sure all plugs are good if not get 9mm ford racing wires and maybe a MSD blaster coil.
All this contributes to the proper burning in fuel and making sure your fuel to air ration is on point for better fuel combustion and fuel economy.
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1994 GT AODE, 3.55, shift kit, BBK H PIPE, K&N, XLerator Performence Mufflers (soon to be Super 44's), MSD(Cap, Rotor, TFI Blaster Coil), and 9mm Ford Racing Spark Plug Wires, Ford Racing B Springs.
Thats funny, because I;ve done literally every single thing you've listed in your "ALSO" section. Even down to the seafoam. And I did clean the connectors with electronics cleaner. I may just take them back. They better give me my money back even though they were installed.
I'm a Advance Auto Parts guy cause i get everything discounted but i would think that you would get your money back.
The only other thing i did was hold onto the tab and try to stick the connectors together and disconnect it over and over again and shove the connectors hard into each other till they clicked or i just couldn't push them back together.
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1994 GT AODE, 3.55, shift kit, BBK H PIPE, K&N, XLerator Performence Mufflers (soon to be Super 44's), MSD(Cap, Rotor, TFI Blaster Coil), and 9mm Ford Racing Spark Plug Wires, Ford Racing B Springs.
You know what, I have had a lot of problems with Autozone giving me regular Mustang parts instead of Cobra parts , but I asked the people on here and was told there is no difference so I figured Autozone couldnt screw this one up. I think I am done going there.
On the other hand, Advance Auto has always got it correct.
1994 Mustang Cobra, O2 sensor problems 
, but I asked the people on here and was told there is no difference so I figured Autozone couldnt screw this one up. I think I am done going there.
