Fuel Failure 17

Hello,  I do have the haynes manual and know that Fuel failure 17 says Throttle Potentiometer, not in operating range. My question would be if I filled regular unleded gas could this be the problem? I usually put in middle grade unleded. Last time I filled up I accidently put in regular unleded.
 
If anybody has any ideas it would be much appreciated.
 
Thanks
James

The fuel grade shouldnt have affected it at all.
Could well be a TPS problem. However, not knowing what kind of vehicle, year or engine size you have, hard to say.