JCI400

When I start my 99 Formula WS6 after sitting a while, the speedometer and tach jump violently to the high end and come back to normal, the gas gauge then drops to E and runs back up where it should be and the trip odometer resets. It used to happen when sitting overnight. Now its happening when it sits for only an hour. Ideas?

2001NBMZ28

Check the battery terminal connections/have the battery load tested. GM issued a TSB on it for the 99's to replace the gauge cluster, but a good battery will make it go away. It's caused by low voltage.

Luder[PAK9]

+1 for bad battery or bad connection.

blu98ta

iTrader: (4)

I had the same thing happen to me just recently, and it was a loose ground wire on the motor. Check those too!

keliente

iTrader: (22)

Ditto. Mine did this too until I replaced the battery. Kind of a weird problem considering the car ran/started fine otherwise!

JCI400

Keliente, you are right, the car starts and runs great.

I pulled the battery the other day to replace the right headlight gear with a metal one, that was fun. I know I got the terminals on the battery correct and tight. The guages were doing it before and after battery removal, so guess I better check how secure the terminals are too.

The volt gauge, (yeah, I know the stock ones aren't that accurate) tells me it sees 12 volts with the engine off and key on.

Danny2tek

iTrader: (1)

mine did that, the battery showed signs of being fine but still replaced it and the problem was solved