Recently whenever I get to 1/2 a tamk of gas or lower my fuel gauge goes haywire. It will be at 1/2 tank when driving and when I come to a stop and then continue on my gauge will drop to empty and sometimes it will come back to 1/2 tank and sometimes it will stay on empty for awhile. No body at Ford can figure out why, I was told the fuel pump and also the sending unit was fine. It has had diagnostic testing and everything checked out. Wondering if anyone else is having this problem or know any suggestions to fix it.

 

The 05's and early '06's have a chronic issue with the stepper motors in the gauges. Google "stepper motors Ford Mustang" and you'll likely get a lot of supporting info. I understand that someone on ebay will replace the stepper motors if you send them the cluster. It didn't seem overly expensive, IIRC.

 

Thanks for the info, I would have never thought it was from the instrument cluster. I'll check into it.

 

Could also be the crappy high-sulfur oil gasoline a lot of companies are selling now. Alot more cars are giving off the rotten egg exhaust smell lately because of this. Its the sulfur and it messes up the resistance in the sending units. Sometimes if I let the gauge get down to a 1/4 tank (I know, I know, its not good to let the tank get that low but it just happens sometimes) the needle will just drop to empty. I have heard running a couple bottles of Chevron Techron through can help dissolve the sulfur deposits and it does seem to help.

 

+1 when i purchased my car, the tach, fuel, and speedometer stepper motors were all crapping out. about $30 on Ebay and a $5 walmart soldering iron, and all's better.