Stardust

By buddy just picked up a 93 Trans Am. Decent car with one issue.

The speedometer will bounce around while driving, and also just sitting still in park. It will bounce up 0-20 mph. We also noticed while it's sitting there doing that in park, the odometer is counting miles as if the car is actually moving like the speedo says.

Any ideas?

Firebrian

Intermittent ground? Alternator/charging system? Other thoughts might be weak battery or a fault in the instrument cluster.

Cpt.Derrek

iTrader: (13)

Fairly certain its a wiring issue. sounds like speed input wire is possibly touching a hot wire or intermittent ground like previously stated. My truck has the same issue but only occasionally when I press in the clutch, I'll see the speedo make a little jump. I know there is a break in the wire somewhere but I don't want to rip out all the wiring to find out. good luck with yours.

hrcslam

You're either getting a false signal to the gauges or the gauge cluster is bad. Hook up a data logger and see if it matches what the gauges are saying. If so, look into a false signal to the PCM. If not, gauge cluster.

01WS6/tamu

iTrader: (37)

Bad cluster had a lot of 93's do that when they got around the 8-10 year old mark.

Check all the block harness grounds also.