Check Engine Light, No codes

[SHO#7]

So, here is one that has me stumped. On my 93 MTX I have a check engine light that will come on when I am at WOT for more than about 5 seconds. It must be in the upper RPM range ( past 4500 I would say ) and will stay on for about 5-10 seconds and go out. I have scanned the car, with my Snap-On scanner and both KOER and KOEO show no codes. Even without shutting the car off since the light had been on.

I would think O2 sensor, since every SHO I have ever had has taken one now and again. I do have an air/fuel ratio gauge connected to the front bank sensor ( bank 2? ) and it functions just like I think it should. On 93 and older Fords I can not get any data stream, so I can not watch the O2 sensors on the scanner.

And advice is appreciated.

The car runs excellent. No driveability issues...

 

[SHOZ123]

My '93 would have the CEL come on and off with no codes. It was a bad fuel injector. While the one bank was going lean to rich because the PCM was adding extra fuel to the other two cylinders, it would light up the light.

Pull your plugs first before changing the O2 sensor and look for a white one or one that is a lot different color than the other two on that bank. I changed mine first and it made no difference.