I have a 1999 F150, 4x2, automatic transmission, supercab with a 4.6 liter 8 cylinder engine.

I have noticed while driving, that my speedometer needle will at times move erratically across the guage without any effect to my actual travel speed. It will move back and forth momentarily then resume the correct speed reading.

I have noticed this on a few occassions within the past two-three months.

I installed a Superchip about four months ago.

Does anyone have an idea what is causing this to occur?

Thanks.

 

i had a friend install a chip in his cobra, and pulled on one of the wires to hard, it was the one for the speedo, and when anyone would get in the passenger seat and step in the right spot it would make the speedo jump around and or not work..

i would try first just to pull the chip, may just be a bad connection...

jim