One day i had a problem with the Tach , it would stop working when i turned on lights. Supposedly a common ground problem that effects tach/gas gauge
Followed instructions on how to fix. Tach works fine now ,but still no effect
on gas gauge .It sits on full .:mad:

One day i had a problem with the Tach , it would stop working when i turned on lights. Supposedly a common ground problem that effects tach/gas gauge
Followed instructions on how to fix. Tach works fine now ,but still no effect
on gas gauge .It sits on full .:mad:
Verify that you DON'T have a full tank of gas.

Verify that your voltage regulator isn't going south. Stock radios take the BRUNT of a failed voltage regulator. If you have an aftermarket radio, the VR can fail and take out several systems in your car (ask ND4SPDLSC). If your VR is a Wells brand, I would suggest replacing it as soon as possible with a Motorcraft.

If your alternator is original, I suggest you replace it.

Once you've verified that your charging system is doing what it's supposed to do, then you can start chasing this gremlin from the dash back to the tank.

Let us all know what the results of your tests are.

I believe the factory EVTM has a troubleshooting test to verify gauge function. If it's not the cluster, then it could be the sender in the tank, which also should have a test outlined in the EVTM.

Don't throw parts at it until you've done some testing. The bad VRs are just good to replace for insurance and probably aren't related to your problem. I had three crappy GP Sorensens before I got a Motorcraft.

The weird thing is that i've owned the car for 7 years and when i bought it
the owner told me the gas gauge always stopped at half a tank. When you filled it the gauge would read full .then as it went down it would stop at half.
He replaced the sending unit,he said it worked fine for 2 weeks then started
the same thing again. Also what is a evtm.How do i do this

I love this site - you guys are so HOT - LVC rocks. Now I don't feel so bad...how many times have I said " I dont know....." and always get a Hottie back to help - SMOOCHES!

MsM8

oh - yeah, how do you do that?! and what is that!!!??

Also what is a evtm.How do i do this

Google = good. The first result for a search of EVTM would have given you the answer: Electrical and Vacuum Troubleshooting Manual.

http://www.drgh02203.general-hosting.com/1992_Mark_VII_evtm.jpg