Please Help - O2 Sensors Gone Bad?

ATTENTION: Okay guys I am in some desperate need of some mechanical advice. I have a 2001 Mustang GT (4.6 SOHC) it has a little over 100k miles on it. It has been driving perfectly fine since I got it, which was a few months ago but yesterday I went into a store for about 15 minutes then I came back out and started the car, it started up just fine but when I hit the gas it didn't rev or move after I put it in gear. I have a K&N air intake so I thought maybe it was the MAF sensor since they are notorious for getting oil clogged in them from the K&N. Well I replaced the MAF sensor and the EGR Valve and the Throttle Position Sensor, still NO LUCK. I also sprayed all the vacuum lines with starting fluid to try to detect a vacuum leak but I don't think it's that either. Basically it's like I'm not getting fuel when I hit the pedal, it sputters, and will NOT go up any hills/inclines it almost comes to a complete stop. Only codes showing up is that all 4 O2 Sensors are bad. Does anyone have an idea as to what this could be caused by? Any input is greatly appreciated.
 
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If your codes are telling you the O2 sensors are bad, and the car has over 100K miles, then that is where you should start. If you wanna test it first, then get a scan tool that does real time diagnostics. They only cost about $200 and you'll be using it a lot in the future anyway. Get one and see exactly what those O2s are doing. Or just go ahead and replace them. The rears are like $40-$50 each at Autozone. Not sure how much the fronts are. Or you can buy a set off Ebay or from someone on Craigslist. So just replace them and see what happens.

The O2s tell your engine what to do as far as fuel is concerned. If they go bad, then your fuel trims will be way off and you'll bog down. So start there and let us know what happens.
 
Does anyone have an idea as to what this could be caused by? Any input is greatly appreciated.


To answer your last question, there are a couple of things that can cause it.

Contaminated fuel
Wrong fuel
A fuel problem causing the motor to run consistently rich or lean (pump, regulator,...)
Neglect in replacing O2 sensor when light first appeared
Neglect in replacing O2 sensors at 50,000 mile intervals

With used cars it's tough to really know. It sounds like all of your O2 sensors are way past due though.
 
To answer your last question, there are a couple of things that can cause it.

Contaminated fuel
Wrong fuel
A fuel problem causing the motor to run consistently rich or lean (pump, regulator,...)
Neglect in replacing O2 sensor when light first appeared
Neglect in replacing O2 sensors at 50,000 mile intervals

With used cars it's tough to really know. It sounds like all of your O2 sensors are way past due though.


Thanks guys! I forgot to update this but I fixed it the other day, it ended up being a bad fuel pump!