Truck is a 2002 F-150. Last week I noticed the speedometer was jumping to the right when I turned the key over and then shortly after the starter started clicking. I replaced the starter and cleaned up all the contacts including the main ground wire that bolts onto the frame. After installing the new starter and charging up the battery, the truck started fien with no movement on the speedometer again. This morning, I jumped in and the speedometer is now jumping to the right and then back to zero again. I have no trouble with it as far as speed reading, its just initially when I turn the key on. I read some stuff about PSOMs but am unsure what my problem could be.
Could this also be a battery issue? The battery is the factory motorcraft and will be 9 years old.

Any help would be greatly appreciated.

UPDATE: This afternoon, I went out and the starter just clicks again. I am guessing its the battery, but am a little thrown off about the speedometer jumping.

 

Battery, alternator, or cables.

Most auto parts places can test the battery and alternator for free in the truck.

 

Thanks. I did take it down there and the battery only was cranking about 120 amps. I didn't realize that the battery would make the speedometer go crazy. The old starter was also bad, making me think either the bad starter took out the battery or the bad battery took out the starter.

Hopefully this will work.

Thanks.